Question

1. The number of hours per week that 200 college students spend on the Internet is grouped into classes (0 − 3),(4 − 7),(8 − 11),(12 − 15),(16 − 19),(20 − 23),(24 − 27) with observed frequencies of 12, 25, 36, 45, 34, 31, and 17. The grouped mean and standard deviation are found from the data. The null hypothesis is that the data is normally distributed. Using the mean and standard deviation, the expected frequencies are found to be 10, 30, 40, 50, 36, 28, and 6

• Calculate the χ 2 .

• What is the number of degrees of freedom?

• Find the 95% confidence level

Answer 1

The given class intervals are discontinues class intervals. So we make it continues.