Question

The distribution of the amount of money spent by students for textbooks in a semester is approximately normal in shape with a mean of $235 and a standard deviation of $20. According to the standard deviation rule, how much did almost all (99.7%) of the students spend on textbooks in a semester?

Answer 1

Answer: $295

Explanation:

Given that,

Amount spent by the students is normal in shape

Mean = $235

Standard deviation = $20

99.7% is within 3 standard deviations of the mean:

= Mean + 3 × Standard deviation

= $235 + 3 × $20

= $235 + $60

= $295

The amount of $295 is spent by all the students on textbooks.