An investor is looking into the staff to customer ratios of sports apparel retailers. He uses:

H0: The firm under investigation has a ratio that is near the industry average.

H1: The firm under investigation has a different ratio, either high or low.

He gathers data from 31 outlets of a particular retailer and calculates an observed t statistic of -2.19. What is the p-value he will use to compare against the significance level?

Scientists in Indonesia do a wide-ranging survey of the population of their local crabs and find that the average is 2crabs per square meter of oceanfloorwith a standard deviation of 0.6.

A local fisher surveys 10 square meters of ocean floorin a particular Indonesian bay.Make a 95%confidence interval for the average number of crabs found per square meter.Here, enter the lower end of the interval.

A brewer is testing the alcohol content of her latest beer, a coffee porter. Her target percentage is 7% and she wants to know to do a two-tailed test to see if there is either too much or too little. She takes a few samples and based on the resulting data calculates an observed z-value of 2.37. What is the p-value she can compare to the significance level to decide whether she is ok or not?

Every year scientists from the Maryland Department of Natural Resources do the Blue Crab Winter Dredge Survey to find out how healthy the population of crabs is in the Chesapeake Bay. It would take a huge amount of time and money to scrape the floor of the entire Bay, so they choose a few places randomly and drop the gear.

Say that they take 41 samples and find that the average number of crabs per square meter of habitat is 9.3 with a sample standard deviation of 1.1. What is the upper edge of a 99% confidence interval for the average number of crabs per square meter?

The average 43" HD TV on Bestbuy.com costs $558.57 with a standard deviation of $363.49. As of April 2021, Samsung is selling a flat 4K UHD for $427.99. What is the Z score for that price?

Lwin is an expert mushroom hunter. Spending 3 hours in the forest yields an average of 13 clumps of "snow fungus," the local favorite. In three hours, what is the probability that Lwin finds 10-16 clumps?