Suppose that a group of 100 consumers are asked to rate how much they liked the taste of a new soft drink on a 5-point scale (where 5 = good taste and 1 = poor taste)and the mean rating was 4.2 with a standard deviation of 1.48.Suppose,further,that the standard error of the mean for this study was 0.15.If you wanted to find the 95 percent confidence interval (two-tailed test),and if the Z-value at the 0.05 level of significance is 1.96,the confidence interval lies between:
A)3.91 and 4.49
B)4.17 and 4.23
C)3.98 and 4.42
D)4.00 and 5.00

Question

Quizplus · Accepted Answer

The 95% confidence interval is calculated as the mean ± (Z-value * standard error). Here, it is 4.2 ± (1.96 * 0.15), which results in the interval 3.91 to 4.49.

Suppose That a Group of 100 Consumers Are Asked to Rate