Multiple choice

1. A certain type of tennis ball is known to have a bounce weight which is normally distributed with a standard deviation of 2 cm. A random sample of 60 tennis ball is tested and the mean bounce height of the sample is 140 cm. Find

1(a). a symmetrical 95% confidence interval for mean bounce height

a.) (140.51,141.39)

b.) (138.49,141.51)

c.) (138.49,139.51)

d.) (139.49,140.51)