Question

The heights of kindergarten children are approximately normally distributed with a mean height of 39 inches and a standard deviation of 2 inches. If a first-time kindergarten teacher finds the average height for the 20 students in her class is 40.3 inches, would that be unusual? Explain.

ANSWER 0.0018

please show step by step ! thank you

Answer 1

P( > 40.3)

= P(( - )/() > (40.3 -  )/())

= P(Z > (40.3 - 39)/(2/))

= P(Z > 2.91)

= 1 - P(Z < 2.91)

= 1 - 0.9982

= 0.0018

Since the probability value is less than 0.05, so it is unusual.