# Question

An investment website can tell what devices are used to access the site. The site managers wonder whether they should enhance the facilities for trading via “smart phones” so they want to estimate the proportion of users who access the site that way (even if they also use their computers sometimes). They draw a random sample of 200 investors from their customers. Suppose that the true proportion of smart phone users is 36%.

a) What would you expect the shape of the sampling distribution for the sample proportion to be?

b) What would be the mean of this sampling distribution?

c) If the sample size were increased to 500, would your answers change? Explain.

a) What would you expect the shape of the sampling distribution for the sample proportion to be?

b) What would be the mean of this sampling distribution?

c) If the sample size were increased to 500, would your answers change? Explain.

## Answer to relevant Questions

For each situation below identify the population and the sample and explain what p and p represent and what the value of p is. Would you trust a confidence interval for the true proportion based on these data? Explain ...From the survey in Exercise 11, a) How would the confidence interval change if the confidence level had been 90% instead of 95%? b) How would the confidence interval change if the sample size had been 300 instead of 200? ...The philanthropic organization in Exercise 21 expects about a 5% success rate when they send fundraising letters to the people on their mailing list. In Exercise 21 you looked at the histograms showing distributions of ...In a really large bag of M&M’s, we found 12% of 500 candies were green. Is this evidence that the manufacturing process is out of control and has made too many greens? Explain. Based on the 80% national retention rate described in Exercise 37, does a college where 551 of the 603 freshmen returned the next year as sophomores have a right to brag that it has an unusually high retention rate? Explain.Post your question

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