A thread manufacturer wants to estimate the mean tensile strength of a particular type of thread. A random sample of 15 examples of the thread are tested. The mean tensile strength of the sample is...

A thread manufacturer wants to estimate the mean tensile strength of a particular type of thread.  A random sample of 15 examples of the thread are tested.  The mean tensile strength of the sample is 7.64 pounds with a sample standard deviation of 0.48 pounds.  Construct a 95% confidence interval for the mean tensile strength of that type of thread.  In the next question, you will enter the upper limit of the interval.  For now, enter the lower limit of the interval, rounded to two decimal places.