Lexie, a bowler, claims that her bowling score is more than140

points, on average. Several of her teammates do not believe her, so she does a hypothesis test, at a5%

significance level, to persuade them. She bowls18

games. The mean score of the sample games is155

points. Lexie knows from experience that the standard deviation for her bowling score is17

points.

• H
• 0
• :140
• ;H
• a
• :>140
• =0.05
• (significance level)

What is the test statistic (z

-score) of this one-mean hypothesis test, rounded to two decimal places?