Question

Baby talk: In a sample of 69 children, the mean age at which they first began to combine words was 16.44 months. with a standard deviation of 9.47 months. Part 1 out of 2 Construct a confidence interval for the mean age at which children first begin to combine words. Round the answers to two decimal places. A 98% confidence interval for the mean age is:__________

Answer 1

A 98% confidence interval for the mean age is:

= ( 13.78, 19.10) months

Explanation:

Confidence interval can be defined as a range of values so defined that there is a specified probability that the value of a parameter lies within it.

The confidence interval of a statistical data can be written as.

x+/-zr/√n

Given that;

Mean x = 16.44 months

Standard deviation r = 9.47 months

Number of samples n = 69

Confidence interval = 98%

z(at 98% confidence) = 2.33

Substituting the values we have;

16.44+/-2.33(9.47/√69)

16.44+/-2.33(1.140054028722)

16.44+/-2.656325886922

16.44+/-2.66

= ( 13.78, 19.10) months

Therefore, A 98% confidence interval for the mean age is:

= ( 13.78, 19.10) months