Question

A sample of 49 sudden infant death syndrome (SIDS) cases had a mean birth weight of 2998 g. Based on other births in the county, we will assume σ = 800 g. Calculate the 95% confidence interval for the mean birth weight of SIDS cases in the county. Interpret your results.

Answer 1

Solution :

Given that,

= 2998

= 800

n = 49

At 95% confidence level the z is ,

= 1 - 95% = 1 - 0.95 = 0.05

/ 2 = 0.05 / 2 = 0.025

Z_/2 = Z_0.025 = 1.96

Margin of error = E = Z_/2* ( /n)

= 1.96 * (800 / 49)

= 224

At 95% confidence interval estimate of the population mean is,

- E < < + E

2998 - 224 < < 2998 + 224

2774 < < 3222

(2774g , 3222g)