Question

1. Cardiac deaths appear to increase after heavy snowfalls. Researchers were interested to see if there would be a difference between the use of a manual snow shovel and a motorized snow blower on heart rates since these are a factor in cardiac deaths. They found previous research that showed the population of manual snow shovel users had a mean maximum heart rate of 145 with a standard deviation of 15 and the population of motorized snow blower users had a mean maximum heart rate of 139 a standard deviation of 20. They had two test subjects clear a driveway with each one using the different tools. Their maximum heart rate is shown below. Which of the results was the most unusual given the population that they were drawn from? What is the probability that we would see that result from someone drawn at random from the population?

Jack used the manual snow shovel and had a maximum heart rate of 175.

John used the snow blower and had a maximum heart rate of 165.

Answer 1

Let X: be the variable for manual shovel

z-score =

Jack had a maximum (at the most) heart rate of 175

P(X < 175 ) = P(Z < )

= P(Z < 2)

Let 'Y' be for snow blower

Jack had maximum rate of 165.

P( Y < 165) = P(Z < )

= P(Z < 1.3)

The probabilities have been using normal distribution probability tables

Since P(X < 175) > P( Y < 165)

We can say that the snow blower result is more unusual than manual shovel.