Question

A random sample of 12 families were asked how many kids they had. The data are given below. According to the US Census, families have on average 2.4 kids per family. What is the p-value for the alternative hypothesis that the average number of kids per family is different than the US Census value

Answer 1

0.308

Explanation:

Given the data:

1, 1, 2, 2, 2, 3, 3, 3, 3, 4, 4, 6

The sample mean and standard deviation :

Sample mean, xbar = (1+1+2+2+2+3+3+3+3+4+4+6) / 12 = 2.833

Sample standard deviation, s = 1.40 ( calculator)

Hypothesis :

H0 : μ = 2.4

H0 : μ ≠ 2.4

The test statistic :

(xbar - μ) ÷ (s/√(n))

(2.833 - 2.40) / (1.40/sqrt(12))

Test statistic = 1.0713

Using the Pvalue from Test score calculator :

df = n - 1 = 12 - 1 = 11

Pvalue(1.071, 11) two - tailed

= 0.3069

= 0.307