A survey of 64 medical labs revealed that the mean price charged for a certain test was Rs. 120, with a standard deviation of 60. Test whether the data indicates that the mean price of this test is more than Rs. 100 at 5% level of significance.

I have solved this question but I don't know whether the answer is correct or not.

H0: mean = 120 (null hypothesis) H1: mean > 100 (alternative hypothesis)

we will use z test as the sample count is more than 30

$z=|120-100|/60/\sqrt{64}\phantom{\rule{0ex}{0ex}}z=2.67$

at 5% of significance, the critical value of z is 1.96. Since the z value we obtained is more than 1.96, so we reject the null hypothesis and therefore the mean price of the test is more than 100

Please tell whether the answer is correct or there is some mistake in this. Help is appreciated.

I have solved this question but I don't know whether the answer is correct or not.

H0: mean = 120 (null hypothesis) H1: mean > 100 (alternative hypothesis)

we will use z test as the sample count is more than 30

$z=|120-100|/60/\sqrt{64}\phantom{\rule{0ex}{0ex}}z=2.67$

at 5% of significance, the critical value of z is 1.96. Since the z value we obtained is more than 1.96, so we reject the null hypothesis and therefore the mean price of the test is more than 100

Please tell whether the answer is correct or there is some mistake in this. Help is appreciated.