Question

The heart rate of a fetus, in beats per second (bps), is an indicator of baby gender. To determine the gender of his kid, Resh decide to buy an at-home heart monitor. For the next 30 days, Resh measures the heart rate of the fetus.   The average heart rate measured over the past 30 days is 129.5 bps. Previous research established that the population’s standard deviations is 20 bps. Also, the previous research suggest that fetal heart rate is normally distributed.

Calculate and interpret the 95% Confidence interval. Show all work to receive credit

Answer 1

Solution :

Given that,

Point estimate = sample mean = = 129.5

Population standard deviation =    = 20

Sample size = n = 30

At 95% confidence level

= 1 - 95%  

= 1 - 0.95 =0.05

/2 = 0.025

Z/2 = Z0.025 = 1.96

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

= 1.96 * ( 20 /  30 )

= 7.16

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

  ± E

129.5 ± 7.16

(122.34, 136.66)  

We are 95% confident that the true mean of the previous research suggest that fetal heart rate is between 122.34 and 136.66 bps.