Null & Alternative hypothesis and Margin of errors

A researcher believes that students who practice taking all of their regular tests on the computer will do better on the State’s final exam which is on the computer than the students taking their regular tests by paper and pencil. Which would be the null hypothesis?

• Ho: The average on the state exam of the students using paper and pencil tests is greater than or equal to the average on the state exam of the students using computer tests.

• Ho: The average on the state exam of the students using paper and pencil tests is greater than the average on the state exam of the students using computer tests.

• Ho: The average on the state exam of the students using paper and pencil tests is less than or equal to the average on the state exam of the students using computer tests.

• Ho: The average on the state exam of the students using paper and pencil tests is less than the average on the state exam of the students using computer tests.

From 1990 to 2000 the average temperature in July in Dallas was 97° F. A researcher believes due to Global Warming that the average temperature is increasing in Dallas. Which of the below could be the alternative Hypothesis?

• Ha: The mean temperature in Dallas in July isn’t 97° F.

• Ha: The mean temperature in Dallas in July is strictly greater than 97° F.

• Ha: The mean temperature in Dallas in July is less than or equal to 97° F.

• Ha: The mean temperature in Dallas in July is strictly less than 97° F.

A researcher believes that students who get less than 8 hours of sleep each night at home have a higher number of school disciplinary referrals by their teachers. What is the alternate hypothesis?

• Ha: The average number of disciplinary referrals by students which had less than 8 hours of sleep is greater than or equal to the average number of disciplinary referrals by student which had 8 or more hours of sleep.

• Ha: The average number of disciplinary referrals by students which had less than 8 hours of sleep is greater than the average number of disciplinary referrals by student which had 8 or more hours of sleep.

• Ha: The average number of disciplinary referrals by students which had less than 8 hours of sleep is less than or equal to the average number of disciplinary referrals by student which had 8 or more hours of sleep.

• Ha: The average number of disciplinary referrals by students which had less than 8 hours of sleep is less than the average number of disciplinary referrals by student which had 8 or more hours of sleep.

A high school administrator determined that 22% of the students worked part-time after school with a ±8% margin of error. If the school has 1420 students, which would represent the possible number of students that work part-time after school?

• 199 to 426 students

• 114 to 312 students

• 195 to 430 students

• 47 to 178 students

The news listed that the average price of a gallon of gasoline in the city is $3.20 with a margin of error. If this correct what two dollar values the average cost of a gallon of gasoline should be between?

• between $3.15 and $3.25

• between $3.04 and $3.36

• between $3.10 and $3.30

• between $3.06 and $3.34