A manufacturer of car batteries claims that the life of the company’s batteries is approximately normally distributed with a standard deviation equal to 0.9 year. If a random sample of 10 of these batteries has a standard deviation of 1.2 years, do you think that σ > 0.9 year? Use a 0.05 level of significance.

A pizza delivery chain advertises that it will deliver your pizza in 35 minutes from when the order is placed. Being a skeptic, you decide to test and see if the mean delivery time is actually more than 35 minutes. For the simple random sample of 14 customers who record the amount of time it takes for each of their pizzas to be delivered, the mean is 37.0 minutes with a standard deviation of 9.9 minutes. Assume that the population distribution is approximately normal. Perform a hypothesis test using a 0.05 level of significance. Step 1 of 3: State the null and alternative hypotheses for the test. Fill in the blank below. Ho: 35 Họ 1 = H₂H = 35

The warranty on a car battery is 30 months. If the breakdown times of this battery are normally distributed with a mean of 40 months and a standard deviation of 8 ​months, determine the percent of batteries that can be expected to require repair or replacement under warranty.    what ​% of batteries can be expected to require repair or replacement under warranty.​ (Round to two decimal places as​ needed.)

The average time taken for your Internet service provider to remotely resolve a trouble ticket has a Normal distribution with a mean of 4.3 hours and a standard deviation of 3.1 hours. What percent of the time can you expect to wait longer than a full 8-hour business day for a resolution?

The MPG (miles per gallon) for a certain compact car is normally distributed with a mean of 30 and a standard deviation of 1. What is the probability that the MPG for a randomly selected compact car would be less than 28?

Suppose a certain population of observations follows a bell-shaped distribution. Based on the 68/95/99.7 rule, what percentage of the data in the population are between three standard deviations below the mean and one standard deviation above the mean?

A manufacturer knows that their items have a normally distributed lifespan, with a mean of 6.9 years, and standard deviation of 1.6 years.The 2% of items with the shortest lifespan will last less than how many years?