hypothesis test

  1. A

    3 Datasets Hypothesis testing

    n = 72 subjects were randomised to 3 treatment groups: A, B, C, so that n = 26 for Group A, n = 29 for Group B, n = 17 for Group C. Measurements were taken before and after treatment. The differences were calculated between the before & after-treatment observations for the 3 treatment groups...
  2. L

    What statistical test should I use?

    Hi there, I'm currently in the process of carrying out a systematic review and I've gathered cost estimates from studies for a specific type of treatment (with two different approaches), I am interested in finding out if these costs have decreased over time. I have 40 cost estimates for the...
  3. H

    Confusing question on z-score for sample mean

    Hey folks, I was hoping someone would understand this better than I do. I am trying to solve the following problem: We are testing the hypothesis that the average gas consumption per day in Billings, Montana is greater than 7 gallons per day; we want 95% confidence. We sample 30 drivers. The...
  4. A

    p values, alpha, and errors

    I was speaking with a classmate about subject heading for this thread and it made me a bit confused. Here are my thoughts: the way I explain p value: probability of observing effect when, in reality, there is no effect. This translates to probability of data given the null (null=there is no...
  5. T

    One or two tailed test?

    Hi, I am currently struggling to decide whether the following problem requires a one or two tailed t test for a hypothesis test. I have uploaded a photo of the data used if needed. 'Test the individual significance of the explanatory variable. You should decide on an appropriate t-test (one...
  6. S

    Whether to use z test or t test

    hi team, I got the following question given below. According to me this should be solved using z test as the sample size is more than 30. But they are using t test. What is the correct method z test or t test? Please advice A social worker wants to know whether the mean annual salary of...
  7. K

    Hypothesis Testing

    I have 8 pre-test results and 8 post-test results but nothing identifying who took which test. How can i test to see if the post-test group feels that they are more skilled after my class?
  8. H

    hypothesis test

    True or False: Referring to the table below, the null hypothesis will be rejected. TABLE An appliance manufacturer claims to have developed a compact microwave oven that consumes an average of no more than 250 Watts. From previous studies, it is believed that power consumption for microwave...
  9. D

    Goodness of Fit Tests - are they really good?

    Hi, after some time of using goodness of fit tests without really thinking about them, I came to this curious question: Normally, it is recommended to have a Null hypothesis which you want to reject. (I.e. the opposite of what you want to show.) However, in Goodness of Fit this is not the...
  10. P

    Hypothesis test problem ?

    Hi all, I want to solve the following problem. But I don't have understand exactly what I have to do. Could you help me please ? A news feed is tested to see if it increases the length of a lizard. 23 lizards eat 12.5 kg of food for two weeks. Once finished the experiment count the length...
  11. J

    Hypothesis testing

    test a claim that each can of soda contains exactly 11 oz. at the 3% level of significance, given that the mean volume of 10 cans of soda is 12.05oz with a known standard deviation of 0.06 oz reject or dont reject?
  12. S

    What statistical analysis to use for a ordinal scale questionnaire?

    Dear Experts, Im a noob when it comes to statistics. So please pardon my lack of knowledge in this post. I need to do a statistical analysis on a set of questionnaires. There are 3 sets of questionnaires for 3 different populations (Human Resource Reps, Managers, Employees). My hypothesis...
  13. M

    sample size calcs - why do these produce different results

    What are the interpretations for each of these? data a; input z p q e; cards; 1.96 0.95 0.05 0.05 ; data b; set a; n=(z*z*p*q)/(e*e); run; proc print; run; ****************************; proc power; onesamplefreq test=z method=normal sides =...
  14. H

    Hypothesis test help.

    The temperature in degrees Fahrenheit of a random group of healthy adults are 97.0 97.4 99.3 97.7 98.6 99.7 97.5 98.7 96.9 97.9 97.3 99.7 97.8 99.5 97.6 97.3 97.3 96.8 At the 0.01 level of significance can we conclude (by using a sign test) that the median temperature of...
  15. R

    Basic question

    Suppose my null hypothesis is “Not more than 50% person prefer milk” and alternate hypothesis is “More than 50% (or majority) prefer milk”. Actually the null and alternate hypothesis are set so only to test whether majority prefer milk or not. Then I set the question in the questionnaire as...
  16. P

    Homework help, want to check my method for probability and hypothesis test

    I would be most obliged if someone would look at my solution and advise if my method and answers are correct. Mean lifetime of brand X bulbs is known to be 4,500 hours with standard deviation of 450 hours. Part A A light bulb is selected at random find the probability that it will last...
  17. S

    Hypothesis testing

    Could you please explain me how to do this exercise step by step? (http://oi57.tinypic.com/w1tv78.jpg) I know that it is a one-sided test and that I should make two hypnotheses H0: μ=20, H1: μ>20. I tried solving this but never got it right. I know it's probably easy but if you could...
  18. W

    Someone please help me with these hypothesis testing questiong!!!

    Hi Everyone, I've got an extra credit for my statistic for social science/psychology, and I've barely hitting the mark to get a pass. So I was given extra credit questions. but I don't really know how to do them. Hope someone could really help me on this! Thanks![/ATTACH]
  19. P

    Appropriate hypothesis test for beta or fractional logistic distributions

    Hi! Thanks to previous suggestions I have determined that my bounded data sets are fit well by beta and/or fractional logistic distributions. I am wondering now, what the appropriate hypothesis tests would be for such distributions? I have been using Kruskall-Wallis and the Mann-Whitney/Wilcox...
  20. C

    Goodness of fit test for a normal ditribution

    In the example from a site I was trying out http://www.cimt.plymouth.ac.uk/projects/mepres/alevel/fstats_ch5.pdf this problem in page 107 about Goodness of fit test for a normal distribution.Question is about analysis of fat content of hambergers. I understand that we need to have the two...