Question

A market research company conducted a survey of two groups of students from different schools. They found that students from school A spent an average of 90 minutes studying daily, while the students from school B spent an average of 75 minutes daily.

They want to find out if the difference in the mean times spent studying by the students of the two schools is statistically significant.
Which of the following sets shows the correct null hypothesis and alternative hypothesis?
1. Null Hypothesis: There is at least some difference in the mean times spent by the schools' students.
2. Alternative Hypothesis: The students from school B spend more time studying than the students from school A.
3. Null Hypothesis: School B students spend more time studying than School A.
4. Alternative Hypothesis: The difference in the mean times spent by the schools' students is 15 minutes.
Null Hypothesis: There is no difference in the mean times spent by the schools' students.
Alternative Hypothesis: There is at least some difference in the mean times spent by the schools' students.
Null Hypothesis: The difference in the mean times spent by the schools' students is 15 minutes.
Alternative Hypothesis: There is no difference in the mean times spent by the schools' students.

Answer 1

Explanation:

Since they want to find out if the difference in the mean times spent studying by the students of the two schools is statistically significant, it means that it is a two directional test. Also called a two tailed test. The hypothesis would be as follows:

Null Hypothesis: There is no difference in the mean times spent by the schools' students.

Alternative Hypothesis: There is at least some difference in the mean times spent by the schools' students.

By using the appropriate symbols, it becomes

The null hypothesis is

H0 : μa = μb H0 : μa - μb = 0

The alternative hypothesis is

Ha : μa ≠ μb Ha : μa - μb ≠ 0