A college admissions director wishes to estimate the mean age of all students currently enrolled. In a random sample of 20 students, the mean age is found to be 22.9 years. From past studies, the standard deviation is known to be 1.5 years, and the population is normally distributed. Construct a 90% confidence interval of the population mean age.

90% confidence interval: (22.35,23.45)

Step-by-step explanation:

We are given the following in the question:

Sample mean, = 22.9 years

Sample size, n = 20

Alpha, α = 0.10

Population standard deviation, σ = 1.5 years

90% Confidence interval:

Putting the values, we get,

(22.35,23.45) is the required 90% confidence interval for population mean age.

b) the dogs need to shift their focus to human scent.

13

step-by-step explanation:

169-1=168

168-3=165

165-5=160

160-7=153

153-9=144

144-11=133

133-13=120

120-15=105

105-17=88

88-19=69

69-21=48

48-23=25

25-25=0

since it took 13times to completely subtract it hence its square root is 13