What is the minimal sample size needed for a 95% confidence interval to have a maximal margin of error of 0.1 in the following scenarios?

What is the minimal sample size needed for a 95% confidence interval to have a maximal margin of error of 0.1 in the following scenarios? ( enter a number. Round up the nearest whole number.)

a preliminary estimate for p is 0.16

there is no preliminary estimate for p

For a binomial experiment with r successes out of n trials, what value do we use as a point estimate for the probability of success p on a single trial? (Enter a mathematical expression.)

p=

What price do farmers get for their watermelon crops? In the third week of July, a random sample of 45 farming regions gave a sample mean of = $6.88 per 100 pounds of watermelon. Assume that σ is known to be $1.96 per 100 pounds.

Find a 90% confidence interval for the population mean price (per 100 pounds) that farmers in this region get for their watermelon crop (in dollars). What is the margin of error (in dollars)? (enter a number. Round to two decimal places.)

lower limit    =

upper limit   = 

margin of error =

Find the sample size necessary for a 90% confidence level with maximal error of estimate E = 0.35 for the mean price per 100 pounds of watermelon. (Enter a number. Round up to the nearest whole number.)

A farm brings 15 tons of watermelon to market. Find a 90% confidence interval for the population mean cash value of this crop (in dollars). What is the margin of error (in dollars)? Hint: 1 ton is 2000 pounds. ( enter a number. Round to two decimal places.)

lower limit    =

upper limit   = 

margin of error =