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A car company developed a certain car model to appeal to young consumers. The car company claims the average age of drivers of this certain car model is26.00 years old. Suppose a random sample of 18 drivers was​ drawn, and the average age of the drivers was found to be 28.70 years. Assume the standard deviation for the age of the car drivers to be 2.3 years. Complete parts a through c below.a. Construct a 95​% confidence interval to estimate the average age of the car driver.The 95​% confidence interval for the average age of the car driver has a lower limit of years old and an upper limit of years old.

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princessesther2011

Answer:

95% confidence interval for the average of the car driver has a lower limit of 27.56 years old and an upper limit of 29.84 years old.

Step-by-step explanation:

Confidence interval = mean + or - Error margin (E)

mean = 28.70 years

sd = 2.3 years

n = 18

degree of freedom = n - 1 = 18 - 1 = 17

confidence level = 95%

t-value corresponding to 17 degrees of freedom and 95% confidence level is 2.110

E = t × sd/√n = 2.110 × 2.3/√18 = 1.14 years

Lower limit = mean - E = 28.70 - 1.14 = 27.56 years

Upper limit = mean + E = 28.70 + 1.14 = 29.84 years

95% confidence interval is between 27.56 and 29.84 years.