A random sample of 12 customers was chosen in a supermarket

A random sample of 12 customers was chosen in a supermarket. The (incomplete) results for their checkout times are shown in the table below. Checkout Time (minutes) Frequency Relative Frequency Cumulative Relative Frequency 4.0 - 5.9 2 6.0 - 7.9 0.25 8.0 - 9.9 10.0 - 11.9 1 12.0 - 13.9 2 TOTALS 12 (a)Complete the frequency table (b) What percent of the checkout times are at least 10 minutes? (c) What percent of the checkout times are between 8 and 10 minutes? (d) What percent of the checkout times are less than 12 minutes?

Solution

Frequency Relative Frequncy Cumalative Frequency 4.0 - 5.9 2 2 6.0 - 7.9   0.25 2.25 8.0 - 9.9 6.75 9 10.0 - 11.9 1 10 12.0 - 13.9 2 12 Total 12 Percentage of checkout atleast 10 mins = (1+2)/12 = 0.25 = 25% Percentage of checkout times are between 8 and 10 minutes = 6.75/12 = 0.5625 = 56.25% Percentage of checkout times are less than 12 minutes = (2+0.25+6.75+1)/12 = 0.8333 = 83.3%