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Choosing which statistical test to use – statistics help.

Choosing which statistical test to use – statistics help.


Choosing which statistical test to use. There are many different tests you can
use in statistics. Sometimes it can be quite difficult to know which is the correct test to use. This video will talk about seven tests you are likely to use. involving means proportions and
relationships. When you are trying to work out which is
the most appropriate test there are three questions you should ask One. What level of measurement was used for
the data we are analyzing. 2. How many samples do we have? 3. What is the purpose of our analysis? I will now explain each of these
questions 1. Data or level of measurement Is our data nominal or interval/ratio? Nominal data is also called categorical,
qualitative or nonparametric Examples of nominal data are color whether parts are defective or not, or preferred type of chocolate. Nominal summary values are usually
stated as frequencies, proportions or percentages. The tests that involve nominal data are: Test for a proportion Difference of two proportions and chi-squared test for independence The other type of data is interval/ratio also called quantitative Examples of interval/ratio data are daily sales figures for choconutties weight of peanuts
or temperature the most common summary value for interval/ratio data is a mean. Tests that involve interval/ratio data are: Test for a mean difference of two means – independent
samples difference of two means – paired and regression analysis. For more help on levels of measurement see our video: “Types of data nominal, ordinal, interval/ratio” Ordinal data can be classified with
nominal or interval/ratio depending on the circumstances. 2. Samples Next we ask how many samples are
involved Is there one sample for which we are testing
the relevant statistic against a hypothesized value or are there two samples which are being compared with each other or is the one sample but each observation
has a measure or score for more than one variable? The same sample is measured twice. If we wish to compare a proportion or
a mean against a given value, this will involve one sample. If we’re comparing two different lots of
people or things such as men and women or people from two different departments then we would have two samples. If we have two sets of information on
the same people of things we would say we have one sample with two
variables. An example is one set of days and
information on how many choconutties are sold and what the temperature was. Or – one set of people and information on their
gender and preferred type of chocolate. Finally we ask What is the purpose of the analysis? We can be testing against the
hypothesized value comparing two statistics or looking for a relationship. Chi-squared test for independence and regression are similar in that they are looking at the relationship between two variables The difference between them is in the
kind of data. If you would summarize the data in s
table, we would use a chi-squared test fo
independence whereas if you would put it on a scatter
plot you would use regression analysis. Here iss an example for each of these
tests. They relate back or out other videos teaching about hypothesis testing. After each description of the scenario
pause the video and see if you can identify the correct
test before we tell you the answer. Helen is still selling choconutties. Example one: sufficient nuts. Helen was concerned whether the quantity
of nuts was sufficient in her choconutties. She took a sample of twenty
packets and found the weight of nuts in each packet Pause the video 1. Data The weight was interval/ratio data. 2. Samples There was just one sample of twenty packets
of choconutties. 3. Purpose.
Helen was comparing against given value Thus, the test she needs to use is
Test for a mean. Example Two Prize tickets In a promotional campaign twenty percent of
all packs of choconutties should include tickets for free prizes. Helen takes a sample of fifty packets and
finds that seven of them have winning tickets Pause the video 1. Data: For each bar we are saying yes or no,
only to be lumped whether or not there is a ticket. This is nominal data from which we get a
sample proportion of seven out of fifty Or 0.14 Samples There is one sample of fifty packets Purpose. Helen is comparing the sample value
against a given value: twenty percent We conclude that the test she needs to use is test for a proportion. Example three Bar longevity compared with nuttabars. Helen thinks her choconutties last longer than the competition, nuttabars. She gets 36 people to eat one of each, and records their eating times. Pause now 1. Data. Helen collects times taken in seconds so this is interval/ratio data. 2. Samples There is one sample of thirty-six people
but with two scores for each person the time for the choconuttie and the time for the nuttabar. 3. Purpose She is looking at whether there iss a
difference in the amount of time taken for each of the bars. Thus the test is difference of two means, paired sample. Example four Defective wrapping from two wrapping machines Helen thinks there is a difference in
performance between the two wrapping machines in her factory.
She checks 200 bars from one machine and 150 bars from the other. For each bar she is seeing if the wrapping is
satisfactory or not She finds that ten out of two hundred
bars from the first machine and nine out of 150 bars from the second machine are badly wrapped. Pause the video Data. The information for each bar is OK or not ok This is nominal data. It has been summarized as frequencies. 2. Samples
there are two independent
samples one sample from each of the two machines 3. Purpose Helen is comparing the proportions from
the two samples We can see that the test is difference of two proportions. Example five Do stickers help sales? Helen is exploring whether having free
stickers makes a difference to sales. She has the sales figures for thirteen
days when she did offer free stickers and ten days when she did not.
Pause and decide on the test Data. For each day Helen has a number or value
corresponding to the sales for that day This is interval/ratio data It is summarized as a mean member of
sales. 2. Samples There are two samples one sample for
days with stickers and one sample for days without. 3. Purpose Helen is comparing the average sales
figures for the two treatments we conclude that the test to use is… Difference of two means independent
samples Example six Are sales affected by temperature? Helen wants to see if there is a
relationship between the daily temperature and sales of choconutties. She has data on sales and temperature for thirty weekdays of sales Pause! Data. Sales and temperature at both interval
variables Samples There is one sample of thirty days with two
measures or scores for each day. Purpose. Helen is interested in the relationship
between sales and temperature This leads us to decide that the test is regression. Example seven Men and women and chocolate preference Helen is thinking of selling dark chocolate, milk chocolate and white chocolate choconutties. She thinks that men and women might have different preferences with regard to type. She collects data from fifty customers, noting down if they are men or women and asking them which variety they prefer. Pause the video and decide. Data. Helen records the type of chocolate and sex of person. These are both nominal variables. Samples. There is one sample of fifty customers but with two measures or variables. Purpose. Helen is looking at whether there is a relationship variables Thus the test is chi-squared test for independence. Those are seven examples of the seven tests
outlined here. There are numerous other statistical
tests and other things may need to be considered, but this summary will help you to
understand what these seven basic tests do and what to look for when deciding
on which test to choose.

100 thoughts on “Choosing which statistical test to use – statistics help.

  1. This is the 2nd time I am watching this .. this is such a useful video… testing ourselves against the examples was an eye-opener… could you please also share when do we use path analysis vs regression.. thank you so very much…

  2. Hi… thanks a million for making the basics so clear.. choosing a test also has got to do with which kind of data is our dependent variable. & the number of variables.. It would really very helpful if you could share info on that. for eg, I havent understood when would we use path analysis & when logistic regression.. it would be of immense help if you could suggest in similar lines

  3. Hi!
    I would request insights from the group regarding my results that involves Andrew Hayes mediation (model 4) and moderation (model1).
    X predictor (marital disaffection), Y outcome (Facebook intrusion) and M as a mediator (commitment).

    I have found that path a (Effect of X on M) is significant, Path B (effect of M on Y is significant), and Path C (original effect of X on Y is significant). However, the 4th requirement of the Mediation that C' is also Significant (effect of X on Y, SHOULD have be reduced or eliminated when M is introduced ). Can I report it as partial mediation ?

    Also with the same variables I have found the moderating (interaction) effect of commitment at all three levels (low medium and high commitment levels).
    Should I use another model that takes into account the mediation and moderation of the same variable? or just individually report both models in the results ?
    Thank you for your time and advice.

  4. Hi there,

    1. My data is interval/ratio (growth rate)
    2. I have 3 samples (3 different methods)
    3. Comparing 3 statistics

    May i know which statistical test should i use
    Thank you.

  5. Truly awesome vedio. If i have a teacher like you i am blessed. But still i feel now as i found you. Teaching is a great art. You have proven. I am curious to know about you.

  6. What statistical methodology do groups like 'The Political Compass' and 'Vote Compass' use to weight questionnaire answers and determine where you fall in x-y space?

  7. Hi, i have five tables (time X temp.) each table has different time (the first one from 0 to 15 min, the second from one to 25 min the third one from 0 to 18 min and so on). Each table starts with the same temp. Value (25°C) and end at the same new temp value (100°C). My question is, how can I calculate the Standard deviations and how can get a real average (time vs. temp) data and graph.

  8. Thank you so much. This would have helped me not be so far behind in my introduction to Statistics course. I am going to pass this video to my former professor.

  9. Thank you very much! I wish I had seen your video during my class and could have shared it with my classmates. Brilliant.

  10. I love love love your Venn diagram approach!!! Thank you so much. I have read quite a few econometric textbooks and they still don't make it anywhere quite as clear as this. Thank you!

  11. What statistics can be use if i want to measure relation between integrity and performance of local parliament members, thank you

  12. I hope someone can help me with this. I cant understand what my lecturer had been teaching and I really need help.
    30 women hv anemia in pregnancy & 15 of them hv history of malaria. 90 hv normal hb lvl pregnancy & 20 of them hv history of malaria. what is the research hypothesis and null hypothesis? suggest a statistical test for testing the null hypothesis.

    is this considered as two sample or one sample?

  13. This is a great video and super helpful, thank you, I've subscribed.

    I'm still confused about what test I need to use though, could you help me? I'll write the problem out in terms of Helen and the chocco nutties:

    Helen wants to know if the number of times someone has eaten a chocco nutty changes their opinion of chocco nutties. She has one group of 12 people and gives each person 22 chocco nutties. After each bar a person eats she asks them if they liked or disliked the bar, and wants to compare if there's a difference between the percentage of the group who enjoyed their first chocco nutty bar vs. their second, their third, their fourth and so on. I get that the liking or disliking of the bar is nominal, but does the fact that it's been changed to the percentage of people who said they liked it change that? Also, what kind of data would the number of chocco nutties the subjects have eaten thus far be catagorised as?

    I'm definitely going to watch your other videos to see if they can help me find the answer but if you, or someone lovely in the comments, knows what test I should do I would super appreciate that!

    xoxo

  14. I am so happy I found this video – you have saved me! When teachers break things down so anyone can understand you are catering for everyone to learn. Thanks Dr Nic  :).

  15. Good day, I would just like to ask what type of Statistical test would be most appropriate for comparing 3 different independent variables. Im doing a MFC research, comparing the voltage and amperage over time of the three microbes (independent V.) to determine which has the highest power generation among the three. Thank you

  16. Thank you very much for this video. I really need this for the upcoming licensure examination for Psychometricians this 29 and 30 and I could say that I’m having issues with Statistical tools 🙂

  17. I found it really help full, I am attending my MPH but can really Understand my instructor in the class but after getting this video wow, I understand it thank you so much.

  18. i think this channel is great for biostatistics,,,,hence i have recommended ur videos to medical students in my medical lecture review for medical students…as i think its simple and had great quality !!https://www.youtube.com/watch?v=OoFknuzmcsw&t=12s

  19. Hi there- is there a playlist that contains videos detailing all of the different tests. I've seen it twice now and don't remember seeing links embedded in the video after describing each test. Maybe I am missing something? But I'd like to learn more in-depth about each type of test

  20. Thanks for the help, but the way you implemented the insulting comments such as "Pause the video if you have any kind of self esteem" end up being, to some extent, directed towards those who actually paused the video and thus had the time to read them…

  21. I've not finished the video yet, but it's been really helpful so far! Breaking it down into those questions has helped me figure out what I'm looking for.

  22. what should i use if im trying to identify if gentrification causes crime?
    i have a gentrified and a non gentrified area
    and have crime statistics for both area from 2015-18
    URGENT thanks!

  23. Why is the answer to Q#3 "paired" and not "independent" …. I got that wrong 🙁

    Otherwise u saved my statistical life .. excellent vid

  24. I'm studying for my comprehensive exam..and found this very useful..thanks. I don't mind the accent at all…

  25. Trying to relate this to sociolinguistics 😱😂☺️ wish me luck for my exam on Monday 😱😱😱 Kiora by the way 🤙🏻

  26. I don't understand the "example 6". Why it is "regression analysis" instead of "difference of two means (paired) ? Isn't it correct to use second one?

  27. 8:42 Helen screaminhg at respondents and, PAUSE THE VIDEO if u have self esteem looooooooooooooooooooooollllllllllllllllllllllllllllllllllllllll

    anyways, thank u so much i am really happy that ur video has taught me alot i was worried about my research papers but now i am feeling satisfied gona subscribe ur channel for sure<3

  28. mam can you please leave a link of video for ANOVA and other related tests? i want to note down details about these tests too, it will be of great favour

  29. so maybe someone can help me with this

    I need to do a study where I will be using two surveys on the same group of people
    both are likert scales: Big five inventory (personality traits) the second on the multifactor leadership questionnaire (they can score either high or low in transformational leadership. What statistical tests should I be using. BTW my degree is in psychology not SPSS lol

  30. Most useful diagram i have found and its so simple. If i found this earlier I wouldn't have had such are hard time following along in class!!!!

  31. Hiii, I need a response quick as my coursework is due on Monday. I’m comparing the effects of 2 dilation different drugs on pupil diameter over a period of 42 minutes. I need to see if the results are significant, which test d I use?

  32. Thank soooooooooooooooooo much for all your videors 😉 , they helped me a lot in analysising mu thesis, though there is one single delimma that gives me headach, Can you tell me what kind of statistique i can use when pairing two diffrents questionnaires?!

  33. Wow, you channel is amazing! Thank you for making something that I thought I will never understand so easy! Three hours of lecture from my professor vs 9 minute video from you.

  34. Wow that Eureka moment!!!! I finally get it 😂😂😂😂 thank you so much!!! I can finish my dissertation in peace now! This is so simple and straightforward 👍

  35. My study is about the preference of grade 11 abm students between the library and the computer lab? Should i use a t-test or chi square ??? Plz need help XD

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