One Population Mean Confidence Interval Sigma

A sample of size 49 has sample mean 35 and sample standard deviation 11. Construct a 98% confidence interval for the population mean using this information.

• 13.34,38.66

• 38.66,31.34

• 31.34,38.66

• 38.66,13.34

A random sample of 120 students from a large university yields mean GPA 2.71 with sample standard deviation 0.51. Construct a 90% confidence interval for the mean GPA of all students at the university

• 1.63,3.79

• 2.63,2.79

• 3.79,1.63

• 2.97,2.63

A random sample is drawn from a population of known standard deviation 11.3. Construct a 90% confidence interval for the population mean based on the information given (not all of the information given need be used)

n= 100, x¯ = 105.2, s = 11.2

• 103.35,107.05

• 93.35,117.05

• 107.05,103.35

• 117.05,93.35

Find the number

z

needed in the construction of a confidence interval:

when the level of confidence is 90%

• 1.64

• 2.58

• 2.33

• 1.96

A random sample of 100 visitors to a popular theme park spent an average of $142 on the trip with a sample standard deviation of $47.50. Which of the following would be the 98% confidence interval for the mean money spent by all visitors to this theme park?

• 
  ($130.77, $153.23)

• 
  ($132.69, $151.31)

• 
  

  ($130.96, $153.07)

• 
  ($140.88, $143.12)

A random sample of 100 visitors to a popular theme park spent an average of $142 on the trip with a standard deviation of $47.5. Which of the following would be the 98% confidence interval for the mean money spent by all visitors to this theme park?

• ($130.77, $153.23)

• ($132.77, $151.43)

• ($132.69, $151.31)

• ($140.88, $143.12)

You sample 12 bugs and find the sample mean is 2.40 cm. You are told the standard deviation is 0.2 cm. Find a 95% Confidence Interval.

• 1.96

• n

• 12

• σ

• .2

• Z

• 2.40

• μ

You sample 12 bugs and find the sample mean is 2.40 cm. You are told the standard deviation is 0.2 cm. Find a 95% Confidence Interval.

• 12

• Z

• 1.96

• μ

• .2

• n

• 2.40

• σ

You sample 16 students in your school, and they average 13 hours of TV a week. Assume the standard deviation is 3. Find a 99% Confidence Interval.

Which of the following is incorrect?

• μ = 13

• σ = 3

• Z = 1.645

• n = 16

The football coach randomly selected ten players and timed how long each player took to perform a certain drill. The times (in minutes) were: 13.2, 5.1, 7.5, 8.0, 12.7, 7.6, 13.8, 14.5, 7.7, and 10.5. Determine a 95 percent confidence interval for the mean time for all players.

• 12.30 < μ < 7.82

• 7.82 < μ < 12.30

• 7.74 < μ < 12.46

• 12.40 < μ < 7.72