Introduction to Statistics

Identify the correct null hypothesis:

Is the proportion of babies born male different from 50%? In a sample of 200 babies, 96 were male. Test the claim using a level of significance of 1%.

• H₀: p = 0.50

• H₀: µ = 100

• H₀: p = 0.48

• H₀: µ = 96

Which of the following represents the appropriate null & alternative hypotheses?

"We want to show that the mean height of women is greater than 64"

• H₀: μ = 64"

  Hₐ: μ ≠ 64"

• H₀: μ = 64"

  Hₐ: μ > 64"

• H₀: p = 64"

  Hₐ: p ≠ 64"

• H₀: p = 64"

  Hₐ: p > 64"

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 access effectiveness. What are the correct null and alternative hypotheses?

• Ho: μ = 21

  Ha: μ < 21

• Ho: p = .20

  Ha: p < .20

• Ho: p =.21

  Ha: p > .21

• Ho: p = .21

  Ha: p < .21

At the Chrysler manufacturing plant, there is a part that is supposed to weigh 19 pounds, on average. The engineers take a sample of parts and want to know if they meet the weight specifications. Their sample's mean weight is 17 pounds What are our null and alternative hypotheses?

• H_o : μ = 17

  H_a : μ ≠ 19

• H_o : μ = 19

  H_a : μ ≠ 19

• H_o : μ = 19

  H_a : μ ≠ 17

• H_o : μ = 17

  H_a : μ ≠ 17

Use the notation to state the alternative hypothesis and null hypothesis: "We suspect that less than 4% of high school students take Statistics."

• H_o : μ = 0.04

  H_a : μ > 0.04

• H_o : μ = 0.04

  H_a : μ < 0.04

• H_o : p = 0.04

  H_a : p < 0.04

• H_o : p = 0.04

  H_a : p > 0.04

A P-value indicates:

• the probability that the null hypothesis is true

• the probability that the alternative hypothesis is true

• the probability of obtaining the observed results (or one more extreme) if the null hypothesis is true

• probability of a Type I error

A principal at a school is worries that his students are below average intelligence. A random sample of 30 students’ IQ scores has a mean of 96. Given that IQ scores are Normally distributed with a mean of 100 and standard deviation of 15, is there sufficient evidence to support the principal’s claim?

What is the null hypothesis?

• μ = 96

• μ = 100

• μ < 100

• μ > 100

A principal at a school is worries that his students are below average intelligence. A random sample of 30 students’ IQ scores has a mean of 96. Given that IQ scores are Normally distributed with a mean of 100 and standard deviation of 15, is there sufficient evidence to support the principal’s claim?

What is the alternative hypothesis?

• μ = 96

• μ < 100

• μ > 100

• μ ≠ 100

The policy of a particular bank branch is that its ATMs must be stocked with enough cash to satisfy customers making withdrawals over an entire weekend. At this branch the expected average amount of money withdrawn from ATM machines per customer transaction over the weekend is $160 with an expected standard deviation of $30. Suppose that a random sample of 36 customer transactions is examined and it is observed that the sample mean withdrawal is $172. Will the ATM be stocked enough for the weekend?

What is the alternative hypothesis?

• μ = $172

• μ < $160

• μ > $160

• μ ≠ $172

The claim being assessed in a hypothesis test

• Null hypothesis
• Alternative hypothesis
• P-Value
• Parameter