Q 8.138. - Elementary Statistics

Question

Shoe and Apparel E-Tailers. In the special report "Mousetrap: The Most-Visited Shoe and Apparel E-tailers" (Foonucar News, Vol. 58 . No. 3. p. 18), we found the following data on the average time, in minutes, spent per user per month from January to June of one year for a sample of $15$ shoe and apparel retail websites. 

Step-by-Step Solution

Answer

It is reasonable to apply the $t-$interval procedure to obtain the confidence interval of the population mean based on the sample.

Step 1: Given information

13.3	9.0	11.1	9.1	8.4
15.6	8.1	8.3	13.0	17.1
16.3	13.5	8.0	15.1	5.8

Step 2: Explanation

Now, draw a probability plot for the given data.  

Now construct a box plot for a given data. 

Step 3: Explanation

Now construct the histogram for the given data. 

The sample size here is moderate $(n=15)$ We can see that there is no outlier in the sample from the graphical representations of the data, and the normal probability plot suggests that the variable under discussion is nearly normally distributed because the plotted points fall roughly along a straight line. As a result, using the $t-$interval approach to calculate the confidence interval of the population means based on the sample is fair.