STATISTICS & PROBABILITY

The mean height of women is greater than 64" (inches). Which of the following represents the null and alternative hypotheses?

A one sample t-test is conducted on Ho: μ = 81.6. The sample has a sample mean = 84.1, s = 3.1, n = 25, and α = .01. State your null and alternative hypotheses.

Perform a hypothesis test on the null hypothesis where μ = 6.9. A random sample of 25 items is selected. The sample mean is 7.1 and the sample standard deviation is 2.4. It can be assumed that the population is normally distributed at α = .01.

A certain telephone company with a target of 5,000 items found that 300 out of the 500 items they randomly chose and tested failed to meet the quality control guidelines. The company would like to test if more than 25% of the target might be out o assurance. What is the appropriate alternative hypothesis at α = 0.05 level?

In problem no. 16, what is the correct null hypothesis?

A survey conducted last year by the barangay health workers showed that 20% of the students smoked. This year, a new survey is conducted on 150 students elected randomly from the same school. It was found out that 35 of them smoke. Test if the claim has decreased at α = 0.01 level. Formulate the correct alternative hypothesis.

In a public junior high school, a study found out that 40% of Grade 7 students are overweight. Is this lower for grade level age if a sample of 100 students was randomly chosen at 0.05 level of significance? What is the appropriate alternative hypothesis?

Ships arriving in Manila Port are inspected by Custom Officials for contaminated cargo. Assume that at a certain port, 15% of the ships arriving in the previous year contained cargo that was contaminated. A random selection of 50 ships in the current year included 5 that had contaminated cargo. Does the data suggest that the proportion of ships arriving in the port with contaminated cargoes has increased in the current year? Use α = 0.01 level. Formulate the alternative hypothesis in sentence form.

Which of the following words suggests a right-tailed test?

A mayor is concerned about the percentage of city residents who express disapproval of his job performance. His political committee pays for a newspaper ad, hoping to keep his disapproval rating below 21%. They will use a follow-up poll to determine effectiveness. What is the correct null hypothesis?