A 95% confidence interval for the average salary of all CEOs in the electronics industry wasconstructed using the results of a random survey of 45 CEOs. The interval was ($97,911, $110,014).To make more useful inferences from the data, it is desired to reduce the width of the confidenceinterval.

Which of the following will result in a reduced interval width?3

A) Increase the sample size and increase the confidence level.

B) Decrease the sample size and increase the confidence level.

C) Decrease the sample size and decrease the confidence level.

D) Increase the sample size and decrease the confidence level

D) Increase the sample size and decrease the confidence level

Step-by-step explanation:

To build the confidence interval, initially we have to find the critical value of Z.

90% confidence interval

We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of .

So it is z with a pvalue of , so

95% confidence interval

We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of .

So it is z with a pvalue of , so

The width is

In which is the standard deviation of the population and n is the size of the sample.

So, as z increses, so does the width. If z decreases, the width decreases. Lower confidence levels have lower values of z.

As n increases, the width decreses.

So the correct answer is:

D) Increase the sample size and decrease the confidence level

s

step-by-step explanation:

answer:

given the linear inequality :

add 2y to both sides we get;

simplify:

add 12 to both sides of an equation;

simplify:

divide both sides by 2 we get;

or

the related equation for the inequality equation [1] is;

y-intercepts defined as the graph crosses the y-axis.

substitute x =0 in [2] to solve for y;

y = 6

x-intercepts defined as the graph crosses the x-axis.

substitute value y = 0 to solve for x;

subtract 6 from both sides we get

multiply both sides by 2 we get;

or

x = -12

now, plot these point (0, 6) and (-12, 0) on graph as shown below and shade the graph below the solid line.