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docker41 [41]
3 years ago
8

A human resource manager for a large company takes a random sample of 60 employees from the company database. Based on the sampl

e she calculates a 95% confidence interval for the mean time of employment for all employees to be 8.7 to 15.2 years. Which of the following will provide a more informative (i.e., narrower) confidence interval than the 95% confidence interval?
A. Using a 90% confidence level (instead of 95%)
B. Using a 99% confidence level (instead of 95%)
C. Using a sample size of 40 employees (instead of 60)
D. Using a sample size of 90 employees (instead of 60)
Mathematics
1 answer:
goldfiish [28.3K]3 years ago
5 0

Answer:

A. Using a 90% confidence level (instead of 95%)

D. Using a sample size of 90 employees (instead of 60)

Step-by-step explanation:

The margin of error of a confidence interval is given by:

M = z*\frac{\sigma}{\sqrt{n}}

In which z is related to the confidence level, \sigma is the standard deviation of the population and n is the size of the sample.

The higher the margin of error, the less precise the confidence interval is.

We have:

A 95% confidence interval, with a sample of 60.

We want to make it more precise:

Two options, decrease z(decrease the confidence level), or increase n(increase the sample size).

So the correct options are:

A. Using a 90% confidence level (instead of 95%)

D. Using a sample size of 90 employees (instead of 60)

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Jenny is comparing the cost of two packages of socks.One package has 8 pairs of socks for $12.Another package has 3 pairs of soc
EleoNora [17]

Answer:

  no

Step-by-step explanation:

The second package costs $2 for each pair of socks. If the first package cost that much, it would be 8×$2 = $16 for 8 pairs of socks. That is not the same as $12 for 8 pairs.

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Another way to look at it is the first package costs twice as much as the second, but has more than twice as many pairs of socks. That means the rates are not equivalent.

6 0
3 years ago
A=1/4 and b=6.<br><br> −8ab=
podryga [215]

Answer:

When a=\frac{1}{4} and b=6:

-8ab=-12

Step-by-step explanation:

-8ab can be seen as -8×a×b. Insert the given values:

-8*\frac{1}{4} *6

Simplify multiplication from left to right:

-8*\frac{1}{4} \\\\\frac{-8}{1} *\frac{1}{4} =\frac{-8}{4} =-2

Insert and solve:

-2*6=-12

:Done

3 0
3 years ago
The sum of two numbers is -10.5.
grandymaker [24]

Answer:

-5 and -5.5;

-12.5 and 2

Step-by-step explanation:

Two negative addends, can be added together to give -10.5.

For example:

(-5) + (-5.5) = -5 - 5.5 = -10.5

Also, it is possible for one of the addends to be negative while the other is positive, and their sum will give us -10.5.

For example:

The sum of -12.5 and 2 will give us -10.5.

We are adding a positive and a negative number here. As usual, we will subtract the smaller number from the bigger number, while the result will carry the sign of the bigger number, which in this case is negative sign.

Thus:

(-12.5) + (2) = -10.5

4 0
3 years ago
A basketball has a circumference of 29.5 inches using 3.14 as an approximation for pie what is the basketball volume to the near
Elena L [17]
It is about 434 cubic inches.

4 0
3 years ago
A city starts with a population of 500,000 people in 2007. Its population declines according to the equation
hjlf

Answer: After 7 years the population will be one-half the initial amount.

Step-by-step explanation:

Given: Initial population = 500,000

The population declines according to the equation:

P(t) = 500,000e^{ -0.099t}, where P is the population in t years later.

One-half the initial amount = 0.5 x 500,000

= 250,000

Put P(t)=250,000, we get

250000=500000e^{-0.099t}\\\\\Rightarrow\ \frac{500000e^{-0.099t}}{500000}=\frac{250000}{500000}\\\\\Rightarrow\ e^{-0.099t}=\frac12\\\\\Rightarrow\ -0.099t=\ln \left(\frac{1}{2}\right)\\\\\Rightarrow\ t=\frac{1000\ln \left(2\right)}{99}=\frac{1000(0.69314)}{99}\\\\\Rightarrow\ t=7.00148\approx7

Hence, After 7 years the population will be one-half the initial amount.

5 0
3 years ago
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