Question

The number of hours spent per week on household chores by all adults has a mean of 28.6 hours and a standard deviation of 8.8 hours. The probability, rounded to four decimal places, that the mean number of hours spent per week on household chores by a sample of 64 adults will be more than 26.75 is:

Answer 1

Solution :

Given that,

mean = = 28.6

standard deviation = = 8.8

n=64

= =28.6

= / n = 8.8/ 64 = 1.1

P( > 26.75) = 1 - P( <26.75 )

= 1 - P[( - ) / < (26.75-28.6) /1.1 ]

= 1 - P(z < -1.68)

Using z table

= 1 - 0.0465

= 0.9535

probability= 0.9535