7. A brisk walk at 4 miles per hour burns an average of 300 calories per hour. If the standard deviation of the distribution is 8 calories, find the probability that a person who walks one hour at the rate of 4 miles per hour will burn the following calories. Assume the variable is normally distributed. Draw the normal curve and label appropriately for each problem. a. P (more than 290 calories) b. P (between 280 and 320 calories) c. P(less than 280 calories) d. Would it be unusual for the person to burn less than 280 calories