Question

4. Each morning a hospital quality-control person checks two pulse oximeters by mounting them on a testing rig that simulates a stable patient. Experience shows that the oximeters give normally distributed readings with variances that match closely and change little, while the mean readings drift from one another over time. In one morning’s check, simple random samples of 5 readings were taken from the first oximeter and of 7 readings from the second. The average oxygen level from the first oximeter was 98.3 with standard deviation 0.31, while the average from the second was 96.1 with standard deviation 0.29.

• Find a 98% confidence interval for the difference in population mean readings from the two oximeters.

• Test whether the population mean readings from the two oximeters are the same.

Answer 1