B. The null hypothesis should be accepted.
C. There is a 7% chance that the null hypothesis is correct.
D. There is a 7% chance of getting a difference between the two groups at least as large as the
observed difference if the new keyboard is really no better at preventing injuries.
E. There is a 7% chance that the observed difference is due to chance.
For a class project, Charlotte recorded the heights of all 28 students in her class and calculated
several statistics. She then realized she made an error recording the height of the tallest person in
the class. She correctly had him listed as the tallest, but needed to add two inches to his recorded
height to correct it. Which of these measures of spread must remain unchanged?
A. Mean absolute deviation
B. Standard deviation
C. Variance
D. Interquartile range
E. Range
- A large company grants its hourly employees pay raises after their six-month performance review.
The amounts of the raises average $0.25 per hour, with a standard deviation of $0.05 per hour. Let
represent the average pay raise of 50 randomly selected hourly employees. Which calculation
would give the approximate probability that is at least $0.30 per hour?
A. P (z ≥ 0.30)
B.
C.
D.
E. This probability cannot be calculated because no information is given about the shape of the
distribution of all pay raises.
The table below shows the daily high temperatures for the month of October for two cities in
different regions of the country.