Question

Basil asks 40 students how many books they bought last year. the chart shows information about the number of books they each bought.

a) what is the percentage of those students who bought 20 or more books?

b) work out an estimate for the mean number of books bought.
please show the full working out.
Number of students who bought 0-4 books= 9
number of students who bought 5-9 books= 10
number of studenst who bought 10-14 books= 13
number of students who bought 15-19 books= 2
number of studenst who bought 20-24 books= 6
please show the full working out

Answer 1

a) 15% b) 10.25

Explanation:

Probability is the likelihood or chance that an event will occur.

Probability = number of expected outcome/total outcome.

a)Total number of student is the total outcome = 40

Expected number of outcome is the number of students who bought 20 or more books = 6 (number of students who bought 20-24 books)

Probability of those students who bought 20 or more books = 6/40 = 0.15

Expressing as percentage = 0.15 * 100 = 15%

This means that 15% of the total students bought 20 or more books

b) Mean is calculated using the formula
`\overline x =(\sum fx)/(N)`

f is the frequency

x is the midpoint of the class interval

N is the total number of students.

Check the attachment for the frequency table.

`\overline x = (410)/(40)\\ \overline x = 10.25`

Mean number of books bought is 10.25