Question

1. The USGA’s specifications for golf balls is that a ball must weigh no more than 1.62 oz.  The manufacturing process for one company’s golf balls produces a normally distributed distribution of ball weights.  To determine if a lot of golf balls produces acceptable balls, a random sample of 25 balls is selected from each lot and tested.  One particular lot has a mean weight of 1.625 oz with a standard deviation of .011 oz.  Using a 1% level of significance, perform a test to determine if this lot of golf balls is acceptable.

Answer 1

= 1.62

n = 25

The test hypothesis is

Now, the value of test static can be found out by following formula:

Since the sample size is n = 25, degrees of freedom on the t-test statistic are n-1 = 25-1 = 24 This implies that

Since, the t distribution is symmetric about zero, so -t{0.01,24}

Since , we fail to reject the null hypothesis