To find the value of the test statistic, we can use the formula for calculating the test statistic for a sample standard deviation:
Test Statistic = (Sample Standard Deviation - Claimed Standard Deviation) / (Sample Standard Deviation / √Sample Size)
In this case, the sample standard deviation is 11.2 bpm, the claimed standard deviation is 12 bpm, and the sample size is 172.
Plugging these values into the formula:
Test Statistic = (11.2 - 12) / (11.2 / √172)
Calculating the values:
Test Statistic = (-0.8) / (11.2 / 13.115) ≈ -0.8 / 0.854 ≈ -0.936
Rounding to two decimal places:
The value of the test statistic is approximately -0.94.