Experiments on learning in animals sometimes measure how long it takes mice to find their way through a maze. The mean time is 18 seconds for one particular maze. A researcher thinks that a loud noise will cause the mice to complete the maze faster. She measures how long each of 10 mice takes with a noise as stimulus. The appropriate hypotheses for the significance test are

(a) H0 : m = 18; Ha : m ≠ 18.

(b) H0 : m = 18; Ha : m > 18.

(c) H0 : m < 18; Ha : m = 18.

(d) H0 : m = 18; Ha : m < 18.

(e) H0 : x– = 18; Ha : x– < 18.

Exercises 26–28 refer to the following setting. Members of the city council want to know if a majority of city residents supports a 1% increase in the sales tax to fund road repairs.

To investigate, they survey a random sample of 300 city residents and use the results to test the following hypotheses:

H0 : p = 0.50 Ha : p > 0.50 where p is the proportion of all city residents who support a 1% increase in the sales tax to fund road repairs.