Arandom sample of 41 car owners results in a mean of 7
years. assume a population a standard deviation of 3.75 years. find
a 95 %confidence interval for the true population mean. identify
thepoint estimate for the mean and margin of error. using this
infofind a 95% confidence interval for the population variance
andstandard deviation. identify the point estimates for both.

Margin of error = ±1.96*std error

= ±1.1479

Confidence interval = Mean ±1.1479

=

Step-by-step explanation:

given that a random sample of 41 car owners results in a mean of 7

years.Assume a population a standard deviation of 3.75 years.

By central limit theorem we can say sample mean will have point estimate as 7 and std error as =

Since population std deviation is known and sample size >30 and also random is assured we can use Z critical value for finding out the margin of error.

95% Z critical value = ±1.96

Margin of error = ±1.96*std error

= ±1.1479

Confidence interval = Mean ±1.1479

=

32

step-by-step explanation:

a

b

d

step-by-step explanation: