A major car manufacturer advertises that its hybrid sedan gets 49 miles per gallon. A consumer organization randomly selects 30 of the sedans and drives them for a month, keeping track of the mileage. It is discovered that the average mileage of the cars is 46 miles per gallon. Does the consumer organization have evidence to begin legal proceedings against the car manufacturer?
If you know the population standard deviation, should you use a t-interval or a z-interval for your confidence interval?
A government agency has received numerous complaints that a particular restaurant has been selling underweight hamburgers. The restaurant advertises that it’s patties are “a quarter pound” (4 ounces). How should the government agency proceed?
What are the conditions for completing a hypothesis test for means? More than one answer is correct. Check all that apply.
What is the purpose of a hypothesis test?
The null hypothesis is a concise mathematical statement that is used to indicate that there is no difference between two possibilities. In other words, there is no difference between certain characteristics of data. This hypothesis assumes that the outcomes of an experiment are based on chance alone. It is denoted as H0. Hypothesis testing is used to conclude if the null hypothesis can be rejected or not. Suppose an experiment is conducted to check if girls are shorter than boys at the age of 5.
The alternative hypothesis is an alternative to the null hypothesis. It is used to show that the observations of an experiment are due to some real effect. It indicates that there is a statistical significance between two possible outcomes and can be denoted as H1 or Ha. Suppose an experiment is conducted to check if girls are shorter than boys at the age of 5. For the above-mentioned example, what would be the alternative hypothesis?
The formula for a hypothesis test is test statistic = (statistic - parameter)/standard deviation
To calculate the p-value is it easier to use the formula or use the calculator?
If the p-value is greater than alpha (significance level), I
If the p-value is less than alpha (significance level), I
Suppose a biologist believes that a certain fertilizer will cause plants to grow more during a one-month period than they normally do, which is currently 20 inches. She performs a hypothesis test at a 5% significance level using the following hypotheses:
H0: μ = 20 inches (the fertilizer will have no effect on the mean plant growth)
HA: μ > 20 inches (the fertilizer will cause mean plant growth to increase)
If the p-value of the test turns out to be 0.002, the conclusion would be:
Suppose the manager of a manufacturing plant wants to test whether a new method changes the number of defective widgets produced per month, which is currently 250. He performs a hypothesis test at a 10% significance level using the following hypotheses:
H0: μafter = μbefore (the mean number of defective widgets is the same before and after using the new method)
HA: μafter ≠ μbefore (the mean number of defective widgets produced is different before and after using the new method)
If the p-value of the test turns out to be 0.27, the conclusion would be:
menu, statistics, stat tests, t-test are the calculator commands to find a