Question

1.)The yearly incomes, in thousands, for 24 random married couples living in a city are given below. Assume the yearly incomes are approximately normally distributed. Use Excel to find the 95% confidence interval for the true mean, in thousands. Round your answers to three decimal places and use increasing order. Yearly Income 59.015 58.962 58.935 58.989 58.997 58.970 59.000 59.014 59.001 59.003 58.992 58.926 59.032 58.958 59.093 58.955 59.003 58.952 59.057 59.056 59.074 59.128 59.001 59.007

2.)In a recent questionnaire about home ownership, a random sample of 545 homeowners were asked about fixed and adjustable rate mortgages, and 268 reported that they have an adjustable rate mortgage. What value of z should be used to calculate a confidence interval with a 95% confidence level?

What value of z should be used to calculate a confidence interval with a 95% confidence level?

z0.10	z0.05	z0.025	z0.01	z0.005
1.282	1.645	1.960	2.326	2.576

Answer 1

Solution:-) We have used excel to determine the confidence interval using command

=CONFIDENCE(alpha, std dev, sample size)

Therefore 95% confidence interval is given by

B) For a 95 % confidence interval the z value will be

As significance level is