You can use a one-sample z-test.
z = (sample mean - population mean)/(standard deviation divided by the square root of the sample size)
With your data:
z = (81.5 - 84)/(10/√75) = ?
I'll let you finish the calculation.
If you use a 1% significant level for a two-tailed test, then the cutoff or critical value from a z-table would be ±2.58. Does your test statistic calculated above exceed either the plus or minus critical value? Draw your conclusions.
I hope this will help.
Cinemark Theaters knows that a certain hit movie ran an average of 84 days in each city, and the corresponding standard deviation was 10 days. The manager of the southeastern part of Dallas was interested in comparing the movie’s popularity in his region with that in all of Cinemark’s other theaters. He randomly chose 75 theaters in his region and found that they ran the movie an average of 81.5 days.
At a 1% significance level, test these hypotheses.
2 answers
1% significance level means 0.01 not 0.1.
2 answers