A financial planner believes his clients received a larger tax refund on their 2023 tax returns than on their 2022 tax returns, on average. The financial planner randomly selects 60 of his clients. Each person provides the amount received from both their 2022 and 2023 tax refund. (Money owed was recorded as a negative.) Which one of the significance tests given below should be used?     

How much does the typical dog owner in the US spend on pet care each year? A random sample of 110 dog owners was surveyed to determine their average annual expenses, including food, veterinary visits, and grooming. The sample mean cost for pet care was $1,045.30 and the standard deviation was $175.20. The 99% confidence interval estimate for the true mean yearly pet care costs for dog owners in the US is between $[a] (lower bound) and $[b] (upper bound). Round your answer to two decimal places.

A nursing student is exploring her employment options after graduation. She is interested in determining if there is any difference in the average pay of nurses in Kentucky versus Ohio. She takes a random sample of 235 BSN nurses working full-time in Kentucky and 235 BSN nurses working full-time in Ohio. She records the annual salary of each person. Which of the following statistical inference techniques should be used?

A car rental company wants to ensure that its fleet of vehicles maintains a high standard of fuel efficiency. Due to slight variations in driving conditions and maintenance, the miles-per-gallon (MPG) achieved by each vehicle follows a normal distribution. To estimate the true mean MPG for a particular vehicle model, five independent tests are conducted on separate days under varied conditions. Which statistical inference procedure should be performed with the resulting data?

Select all that are true.

A new program claims that it decreases the hours of in-school suspension for at-risk middle school students. A small study using 10 students failed to find a statistically significant decrease. If, in fact, the mean in-school suspension hours is decreased by this program, this study’s conclusion is an instance of

How much does a typical household in the US spend on utilities each month? A random sample of 85 US households was surveyed to determine their average monthly spending on utilities, including electricity, water, and gas. The sample mean monthly utility bill was $135.40 and the standard deviation was $24.75. The 99% confidence interval estimate for the true mean monthly utility bill for US households is between $[a] (lower bound) and $[b] (upper bound). Round your answer to two decimal places.

Select the correct conclusion. A consumer group randomly selected 20 college textbooks and looked up the prices for each of them on two different internet web sites.  They tested for differences in prices between the two web sites at a 0.05 level of significance and calculated a p-value of 0.03.  What should they conclude?

The waste produced by a process historically had an average weight of 3.2 pounds. It is suspected that the aging of the equipment used in the process has affected amount of waste in recent years. Suppose you take a random sample of 36 runs of the process, and you find that the sample mean of their weight of waste is 3.8 pounds, with a sample standard deviation of 0.75 pounds. The standard error of the (sample) mean is  ­­­­­[a] pounds. (Round your answer to 3 decimal places.)

Is it easier to hula hoop with a light-weight hula hoop than a weighted hula hoop? To investigate this question, 80 adults were randomly selected. Each person hula hooped with both the light-weight hula hoop and the weighted hula hoop. The time the hula hoop was kept in motion was recorded in seconds. Which one of the significance tests given below should be used?