3. The heart rate of a healthy lion is normally distributed with a mean of μ=40 bpm. One of the lions' heart rates at the Columbus Zoo is randomly checked by a veterinarian 6 times during a week. The lion's heart rate showed a sample mean of x=36.5 bpm and s = 4.2. At the 5% level of significance, test the claim that this lion's heart rate is lower than average.