Statistics Review Sheet

Question 1

The manager at Ally's grocery received complaints from her cashiers at the grocery that many customers who used the express check-out lane have more than the stipulated number of items for the lane. The express check-out lanes are limited to customers purchasing 10 or fewer items. A recently taken random sample of 150 customers entering express lanes at this supermarket found that 84 of them had more than 10 items.

Requirement(s):

1) What is the point estimate of the mean number of customers who enter the express lanes with more than 10 items?

2a) Construct a 99% confidence interval for the percentage of all customers at this supermarket who enter express lanes with more than 10 items

2b) What does the 99% confidence interval mean from part (2a)?

Question 2

Lotus weight loss clinic have been using radio advertisements to advertise their new weight lost program for the past 12 months. The managing director has asked the sales team to assess the effect of these advertisements on sales for that year. Consider sales amount as the dependent variable and the number of advertisements as the independent variable. The sales amount (in '000) and the number of advertisements are shown below.

\f