A manufacturer claims that the mean lifetime of a bulb is 1000 hours. A sample of 25 bulbs has a mean life of 980 hours and a standard deviation of 50 hours. At 5% significance, is the claim valid?

A die is rolled 120 times, and the following outcomes were observed:

Test whether the die is fair at a 5% level of significance. What is the calculated chi-square statistic?

Let A be a matrix. Then which of the following is true

An HR manager is interested in checking the effectiveness of a training program on the sales team. The appropriate test for checking the effectiveness of the training program is: