Gentle Ben is a Morgan horse at a Colorado dude ranch. Over the past 8 weeks, a veterinarian took the following glucose readings from this horse (in mg/100 ml).

95

86

84

105

97

108

86

87

The sample mean is x 93.5. Let x be a random variable representing glucose readings taken from Gentle Ben. We may assume that x has a normal distribution, and we know from past experience that = 12.5. The mean glucose level for horses should be = 85 mg/100 ml. Do these data indicate that Gentle Ben has an overall average glucose level higher than 85? Use = 0.05.

What sampling distribution will you use? Explain the rationale for your choice of sampling distribution.

a) The standard normal, since we assume that x has a normal distribution with unknown .

b) The Student's t, since we assume that x has a normal distribution with known .

c) The standard normal, since we assume that x has a normal distribution with known .

d) The Student's t, since n is large with unknown .