Question

Please, help me. Thanks.
Subject: Hypothesis testing and margin of errors

Answer 1

See below

Explanation:

Problem 4

`H_0:\mu=145\\H_a:\mu>145`

The null hypothesis,
`H_0`, comes from the fact that the nurse initially thinks that the average height of 7th graders is equal to 145 cm.

The alternative hypothesis,
`H_a`, comes from the fact that the average height may be greater than 145 cm since the nurse measured the average height to be 147 cm from the random sample.

Problem 5

`H_0:\mu\geq273\\H_a:\mu<273`

The null hypothesis,
`H_0`, comes from the fact that the manufacturer initially thinks that the mean lifetime of a certain type of batteries is at least 273 hours.

The alternate hypothesis,
`H_a`, comes from the fact that the sample taken may show that it's actually less given a sample mean of 270.5 hours.

Problem 6

The mass population data set would be most suitable because the average score of a test comes from all those who have taken the test while the sample is the class with 25 students. That sample represents the population of all those that have taken the test.

Problem 7

Because it would take a lot of time and money to check every single child in Africa, it would make the most sense to use the sample data set where your samples come from each village and those samples have the children from each village.

Problem 8

This is a population characteristic because the sample that Sarah took for the average number of children per family represents the entire population.

Problem 9

This is a sample characteristic because the size of the sample was clearly large, this was a study, and other claims made.