9.1 A single population mean using the normal distribution  (Page 9/20)

Identify the following:

1. $\overline{x}$ = ______
2. σ = ______
3. n = ______

In words, define the random variable X .

In words, define the random variable $\overline{X}$ .

Which distribution should you use for this problem?

Construct a 90% confidence interval for the population mean weight of the heads of lettuce. State the confidence interval, sketch the graph, and calculate the error bound.

Construct a 95% confidence interval for the population mean weight of the heads of lettuce. State the confidence interval, sketch the graph, and calculate the error bound.

In complete sentences, explain why the confidence interval in [link] is larger than in [link] .

In complete sentences, give an interpretation of what the interval in [link] means.

What would happen if 40 heads of lettuce were sampled instead of 20, and the error bound remained the same?

What would happen if 40 heads of lettuce were sampled instead of 20, and the confidence level remained the same?

$\overline{x}$ = _____

n = _____

________ = 15

In words, define the random variable $\overline{X}$ .

What is $\overline{x}$ estimating?

Is ${\sigma }_x$ known?

As a result of your answer to [link] , state the exact distribution to use when calculating the confidence interval.

How much area is in both tails (combined)? α =________

How much area is in each tail? $\frac{\alpha }{2}$ =________

Identify the following specifications:

1. lower limit
2. upper limit
3. error bound

The 95% confidence interval is:__________________.

Fill in the blanks on the graph with the areas, upper and lower limits of the confidence interval, and the sample mean.

In one complete sentence, explain what the interval means.

Using the same mean, standard deviation, and level of confidence, suppose that n were 69 instead of 25. Would the error bound become larger or smaller? How do you know?

Using the same mean, standard deviation, and sample size, how would the error bound change if the confidence level were reduced to 90%? Why?