Stats homework please help

Question

1. The number of hours spent on a computer is normally distributed with a mean of 7 hours and a standard deviation of 1 hour based on a given survey. A survey participant is randomly selected. Find P(x>10).

(a) .0013 (b) .9987 (c) 0 (d) 1

1. Find the indicated probability: P(z<.73)

(a) .61 (b) .7673 (c) .7967 (d) .2327

Answer 1

P(x > 10)

Compute z-statistic for x = 10, where z-statistic = (x - mean)/standard deviation

z = (10-7)/1 = 3

P(x > 10) = P(z > 3) = P(z < -3) = 0.0013.

P(z < 0.73) - 0.7673