TRUE OR FALSE 4-8

4. Given a normal population with m = 125, s = 15 and n = 25, the P(x-bar > 127) = 0.2514.

5. If floodlight life is normally distributed with mean 3500 hours and standard deviation of 200 hours,

then the proportion of those lasting longer than 4000 hours is 0.062.

6. It is correct to say that the standard error of the mean is also the standard deviation of a

sampling distribution of means.

7. P(-0.5 < Z < -0.3) = 0.0736.

8. For normally distributed I.Q.'s with mean of 100 and standard deviation of 16, the probability that 25

randomly selected individuals have an average I.Q. less than 95 is 0.0594.