Question

4. Another doctor claims that the mean height of 2-year-old boys is greater than 34 inches. A random sample of 320 2-year-old boys revealed that their mean height is 33.8 inches. Knowing that the standard deviation of all 2-year-old boys is 1.44 inches, test the doctor’s claim at the 10% level of significance.

Answer 1

Answer:

= 34 ,   = 1.44

n= 320, = 33.8

= 0.10,  

null and alternative hypothesis is

Ho:   34

H1:   > 34

formula for test statistics is

z = - 2.4845

test statistics : Z = -2.48

calculate P-Value

P-Value = 1 - P(z < -2.48)

using normal z table we get

P(z < -2.48) = 0.0066

P-Value = 1 - 0.0066

P-Value = 0.9934

Decision rule is

Reject Ho if ( P-Value) ( )

here, ( P-Value = 0.9934 ) > ( = 0.10 )

Hence, Fail to reject the null hypothesis.

There is not enough evidence to conclude that the mean height of 2-year-old boys is greater than 34 inches.