1. Historically, the grade distribution on a final exam for a math class has been as follows: Historically, Across Department As Bs Cs Ds Fs 15% 20% 40% 15% 10% After implementing a new teaching method, the final exam grade distribution (in counts) for 300 students was as follows: As Bs Cs Ds Fs 60 50 130 40 20

please show working out. Thank you    A University has put in place a 4 week course of lunchtime exercise breaks for its staff to see if its employees’ job satisfaction can be improved. To measure the effectiveness of this program, 10 randomly selected staff in the program were surveyed about their feelings at work, once at the start of the program and again after the course. Higher scores indicate higher satisfaction. The job satisfaction index results for this group were:    Staff 1 2 3 4 5 6 7 8 9 10 Before 34 28 29 45 26 27 24 15 15 27 After 33 31 36 46 32 34 28 26 19 37 Use a test of significance at 5% level to decide if the program has improved the employee’s job satisfaction on average. Show your graphical evidence, if needed, and clear conclusion.   - please sketch the curve as well. thank you

What statistical methods are typically used in an inferential study?

You want to compare differences in prior arrests across ethnicity in your study, you measured ethnicity as white =0 black =1 hispanic=2, and other =3. Prior arrests was recorded as the number of prior arrests. which test would you perform to see if arrests differ across diffrent ethnic categories? A. ANOVA B. T-test

Explain the difference between a one-tailed and two-tailed significance test. When is it appropriate to use each test?

what is the value of the test statistic for this test?

which statistical analysis correctly analyzes the repeated measures (also known as within subjects) design?

A statistician changes her level of significance from .001 to .05.  What impact will this change have on her risk of making a Type I and Type II error?  Is the change in the level of significance a good decision?  Why or why not?