Question

A study examined the effect of exercise on how students perform on their final exam in statistics. The P-value was given as 0.87.

a) State null and alternative hypotheses that could have been used for this study.
b) Do you reject the null hypothesis?
c) What is your conclusion?
d) What other facts about the study would you like to know for a proper interpretation of the results?

Answer 1

please show any attempted work

Answer 2

lets start with the null hypothesis.
null hypothesis : exercise has no effect on final exam grade .
alternative hypothesis : exercise does have an effect on final exam grade.

Answer 3

you have some flexibility with the alternative hypothesis , though.

Answer 4

oh okay, i was confused as to how to start that, if thats the answer for A then for B would i say yes i reject the null because the p value is .87 or 87% which is strong evidence against it

Answer 5

actually, thats a pretty high p value.
first lets pick a significance level

Answer 6

okay

Answer 7

oh wait, because its high we have to fail to reject it

Answer 8

right

Answer 9

but you first have to pick a significance level
for example, at the 5% significance level we fail to reject the null hypothesis, since
p = .85 > .05

Answer 10

okay so heres what i have so far for my answer:
A) null hypothesis = exercise has no effect on the final exam
alternative hypothesis = exercise has effect on the final exam
B) significance level = 5% the p value is .87 which is 87%
we fail to reject the null hypothesis because 87% > 5%

Answer 11

Small p values provide evidence against the null hypothesis because they say the observed data are unlikely when the null hypothesis is true. We apply the following conventions:
When p value > .10 then the observed difference is "not significant"
When p value <= .10 then the observed difference is "marginally significant"
When p value <= .05 then the observed difference is "significant"
When p value <= .01 then the observed difference is "highly significant"
Use of "significant" in this context means "the observed difference is not likely due to chance."

Answer 12

looks good.

Answer 13

okay now conclusion, give me a minute to compute this

Answer 14

wait how am i supposed to find a z score without any of

Answer 15

the info (mean, population, etc)

Answer 16

you can make part a) more precise.
Null hypothesis : students who exercise score the same average score on final statistics exam as students who don't exercise.

Answer 17

how can i find the z score to make a conclusion if there is no other info then the p value

Answer 18

the p value is the probability of getting *that* test statistic z score or smaller.

Answer 19

there are two types of p values, one tailed test or two tailed test.

Answer 20

oh okay so since .87>.05 we have enough evidence to fail to reject the null hypothesis. The stat conclusion is to accept the null hypothesis and the contextual is that exercising doesn't effect your grade of

Answer 21

Lets assume for the sake of argument.
Ho : Students who exercise have same average score as national mean .
Ha: Students who exercise score on average higher than national mean.

we take a sample of students who exercise, and find that the p value of their score is
p =.87

Answer 22

wait is my conclusion not right?

Answer 23

yes your conclusion is correct