Suppose a study estimated the population mean for a variable of interest using a 99% confidence interval. If the width of the estimated confidence interval( the difference between the upper limit and the lower limit) is 600 and the sample size used in estimating the mean is 1000, what is the population standard deviation?

Population standard deviation, = 3683.063 .

Step-by-step explanation:

We are given that the width of the estimated confidence interval i.e. 99% is 600 and the sample size used in estimating the mean is 1000 which means ;   n = 1000 and width = 600

We know that Width of confidence interval = 2 * Margin of error

Margin of error = = 2.5758 * {because at 1% significance level

                                                                          z table has value of 2.5758 .}

Therefore,  600 = 2 * 2.5758 *

      ⇒ = = 3683.063 .

Hence, the Population standard deviation = 3683.063 .

answer: city needs 2.4 inches of rainfall more to match the record of 40 inches.

step-by-step explanation:

since we have given that

total annual rainfall a city record = 40 inches

this year, total rainfall recorded = 37.6 inches

number of inches of rainfall   is needed to match the record of 40 inches is given by

hence, city needs 2.4 inches of rainfall more to match the record of 40 inches.

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.