I give my class an exam that I know from years of experience yields µ=78 and 𝞂 = 7. My present class of 32 obtains a mean of 82. Am I correct in assuming that this is a superior class? Using a=.05
a. Which test is appropriate (independent samples t, paired t, or z)?
b. What tail is used based on the wording of the question?
c. What is the df (if applicable)?
d. What is the critical t or z value?
e. What is the decision when the Obtained score = 3.233 (please give the "formal" decision sentence as shown on assignments and PP)
f. Is this class superior to the “population” of scores (don't need the full summary)?
2 When hand calculating a t-test, for your “Decision” you calculate/ obtain a t-test of -6.769 and found a Critical t value of of 3.50 at 95% confidence level: (all discussed in book and written PP)
1) is this a significant finding or not, why?
2) indicate how the “p” would be reported/shown in summary:
3) what is the direction of the relationship based on these numbers (this direction is not referring to it being a 1 or 2 tail, don't have that info)? .
Question 21 4 ptsIn a study of crime, the FBI found that an average of 63.2 Americans had been victims of crime during a 1-year period with a sample standard deviation of 7.50. This result was based on a sample of 1,105 adults, alpha of .05.
Please provide the following information. You will need to do some calculations on paper, but do not need to show every step
1) What is the standard error?
2) What is df AND the critical t (since it's a sample SD)?
3) Provide the full Confidence Interval at the 95% Confidence Level
4) Provide a sentence Summary
- Is the Z-test or one of the t-tests used most frequently in “real” research, and why? ALSO briefly explain the relationship between a critical t that has an “n” of 121 or greater and the Z critical value?
Sample Solution