a. In constructing 95% confidence intervals for means, what do we expect will be

Question

a. In constructing 95% confidence intervals for means, what do we expect will be true over the long run? (select all that apply; you have two attempts)

5% of the time, the population mean will fall inside the confidence interval.95% of the time, the population mean will fall outside the confidence interval.95% of the time, the population mean will fall inside the confidence interval.5% of the time, the population mean will fall outside the confidence interval.

b. In constructing 90% confidence intervals for means, what do we expect will be true over the long run? (select all that apply; you have three attempts)

(Hint: Drawing a diagram of a confidence interval and considering scenarios in which the population mean is inside or outside the interval might help.)

90% of the time, the difference between the sample mean and population mean will be more than the margin of error.90% of the time, the difference between the sample mean and population mean will be less than the margin of error.10% of the time, the difference between the sample mean and population mean will be greater than the margin of error90% of the time, the sample mean and the population mean will be exactly equal to each other.10% of the time, the difference between the sample mean and population mean will be less than the margin of error.

Acrylic bone cement is sometimes used in hip and knee replacements to fix an artificial joint in place. The force required to break an acrylic bone cement bond was measured for n = 50 specimens under specified conditions, and the resulting mean and standard deviation were 303.99 Newtons and 41.97 Newtons, respectively.

Construct an "approximate" 95% confidence interval for the true average breaking force of the acrylic bone cement under the specified conditions, using t-critical = 2 as the approximate critical value.


Lower endpoint:  Upper endpoint:  
Note: Round your these endpoints to the nearest whole number.

Explanation / Answer

a)

option C)

95% of the time, the population mean will fall inside the confidence interval. is correct

b)

option B) is correct

.90% of the time, the difference between the sample mean and population mean will be less than the margin of error

c)

mean = 303.99 Newtons and s = 41.97 Newtons, , n = 50

(303.99 - 2* 41.97/sqrt(50), 303.99 + 2* 41.97/sqrt(50))

=(292.1190 ,315.860908)

lower - 292.1190

upper - 315.860908

Pelase rate

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