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Which distribution should you use for this problem ?

Construct a $95\%$ confidence interval for the population proportion of households where the women make the majority of the purchasing decisions. State the confidence interval, sketch the graph and calculate the error bound.

List two difficulties the company might have in obtaining random results, if this survey were done by email.

Which distribution should you use for this problem?

Suppose we have data from a sample. The sample mean is $15$, and the error bound for the mean is $3.2$. What is the confidence interval estimate for the population mean?

Suppose $250$randomly selected people are surveyed to determine if they own a tablet. Of the $250$surveyed, $98$reported owning a tablet. Using a$95$% confidence level, compute a confidence interval estimate for the true proportion of people who own tablets

A student polls his school to see if students in the school district are for or against the new legislation regarding school uniforms. She surveys $600$students and finds that $480$are against the new legislation.

a. Compute a $90$% confidence interval for the true percent of students who are against the new legislation, and interpret the confidence interval.

b.In a sample of $300$students,$68$% said they own an iPod and a smartphone. Compute a $97$% confidence interval for the true percent of students who own an iPod and a smartphone.

Suppose an internet marketing company wants to determine the current percentage of customers who click on ads on their smartphones. How many customers should the company survey in order to be % confident that the estimated proportion is within five percentage points of the true population proportion of customers who click on ads on their smartphones?

Suppose average pizza delivery times are normally distributed with an unknown population mean and a population standard deviation of six minutes. A random sample of $28$pizza delivery restaurants is taken and has a sample mean delivery time of $36$minutes.

Find a $90$% confidence interval estimate for the population mean delivery time.

Table $8.2$shows a different random sampling of $20$cell phone models. Use this data to calculate a $93$% confidence interval for the true mean SAR for cellphones certified for use in the United States. As previously, assume that the population standard deviation is σ= $0.337$.