contestada

Sally gets a cup of coffee and a muffin every day for breakfast from one of the many coffee shops in her neighborhood. she picks a coffee shop each morning at random and independently of previous days. the average price of a cup of coffee is $1.40 with a standard deviation of 30¢($0.30), the average price of a muffin is $2.50 with a standard deviation of 15¢, and the two prices are independent of each other. what is the standard deviation of the amount sally spends on breakfast each day? round to the nearest cent.

Respuesta :

Kalahira
$0.45 The sum of the mean and standard deviations of two independent and uncorrelated standard deviations is simply their sums. Nothing special at all to do. So the mean and standard deviation for the coffee is $1.40 and $0.30 and the mean and standard deviation of the muffin is $2.50 and $0.15. So the mean of her breakfast is $1.40 + $2.50 = $3.90 and the standard deviation is $0.30 + $0.15 = $0.45. And therefore the standard deviation of her breakfast is $0.45

Otras preguntas