2. (14 points) Imagine there is a math problem that has been given to many college students across the country and the nationwide mean time to solve the problem is 110 seconds. You take a random sample of 27 students who been through a math skills workshop (to train them to solve math problems quickly) and give them this problem to solve. You believe that these students will be able to solve the problem more quickly than the national average. a. What is the nondirectional null hypothesis in symbols? I have started it for you. H0:mathikillsworkthopitudens b. What is the nondirectional altemative hypothesis in symbols? 1 have started it for you. H1:mathsitith workikiop thadent c. With a two-tailed t-test with an alpha level of .05 , and a sample of n=27, what are the degrees of freedom and the critical value of t ? Degrees of freedom = Critical value of t= d. When you test the sample of 27 students, you find that the mean time to solve the problem is 102.1 seconds and the standard deviation is 15.89 . Calculate the value of t. SHOW YOUR WORK. Parts e. - k. are on the next page..... e. Would you reject the null hypothesis? (circle one) YES NO f. Would you conclude that there was a significant difference between the population mean for the time to solve the problem and the mean of your sample? (circle one) YES NO g. Imagine you write this for a scientific journal. Fill in the blanks: t1=,0....two-tailed. h. What is the effect size (using the estimated d) for this example? Show your work. i. How would you characterize (evaluate) this effect size? j. If you decided to use a one-tailed test, what is the directional null hypothesis in symbols? H0:mathsskillsworkshiopstudents k. If you decided to use a one-tailed test, what is the directional alternative hypothesis in symbols? H1:mathskillsworkshiopstudents.

1. 2. (14 points) Imagine there is a math problem that has been given to many college students
across the country and the nationwide mean time to solve the problem is 110 seconds. You take a
random sample of 27 students who been through a math skills workshop (to train them to solve
math problems quickly) and give them this problem to solve. You believe that these students will
be able to solve the problem more quickly than the national average. a. What is the
nondirectional null hypothesis in symbols? I have started it for you.
H0:mathikillsworkthopitudens b. What is the nondirectional altemative hypothesis in symbols? 1
have started it for you. H1:mathsitith workikiop thadent c. With a two-tailed t-test with an alpha
level of .05 , and a sample of n=27, what are the degrees of freedom and the critical value of t ?
Degrees of freedom = Critical value of t= d. When you test the sample of 27 students, you find
that the mean time to solve the problem is 102.1 seconds and the standard deviation is 15.89 .
Calculate the value of t. SHOW YOUR WORK. Parts e. - k. are on the next page.....
e. Would you reject the null hypothesis? (circle one) YES NO f. Would you conclude that there
was a significant difference between the population mean for the time to solve the problem and
the mean of your sample? (circle one) YES NO g. Imagine you write this for a scientific journal.
Fill in the blanks: t1=,0....two-tailed. h. What is the effect size (using the estimated d) for this
example? Show your work. i. How would you characterize (evaluate) this effect size? j. If you
decided to use a one-tailed test, what is the directional null hypothesis in symbols?
H0:mathsskillsworkshiopstudents k. If you decided to use a one-tailed test, what is the
directional alternative hypothesis in symbols? H1:mathskillsworkshiopstudents