Question

The mean number of touchdowns per football game is 3.7 with a population standard deviation of 0.9. A random sample of 31 football games was taken and the probability that the mean number of touchdowns for the sample will be more than 3.9 was found. Was the probability a Left-tail, Right -tail or Interval Probability

Answer 1

Right Tail

0.106

Explanation:

The word exceeds means greater than, which are both key words meaning Right-tail probability. With a right tail probability you must subtract the probability from one.

To find the probability a z-score must first be computed using the formula z=x¯−μx¯σx¯

σx¯=0.93‾√1=0.16

z=3.9−3.70.16=1.25

Answer 2

Right Tail

P(x>3.9)= 0.108

Explanation:

In excel, type =NORM.DIST(3.9, 3.7, 0.162, TRUE).