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3 years ago

Evaluate the following expressions for a=-3 | b=1/2 | c= 3/5 | d=-4.

Mathematics

1 answer:

Anton [14]3 years ago

7 0

Step-by-step explanation:

1.= 2×-3+2×1÷2

= -6+1

=-5

2. 5×-3×3÷5-2×1÷2

=-9-2

=-11

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Determine the margin of error for a 90% confidence interval to estimate the population mean when s = 40 for the sample sizes bel

Ann [662]

Answer:

a) The margin of error for a 90% confidence interval when n = 14 is 18.93.

b) The margin of error for a 90% confidence interval when n=28 is 12.88.

c) The margin of error for a 90% confidence interval when n = 45 is 10.02.

Step-by-step explanation:

The t-distribution is used to solve this question:

a) n = 14

The first step to solve this problem is finding how many degrees of freedom, we have. This is the sample size subtracted by 1. So

df = 14 - 1 = 13

90% confidence interval

Now, we have to find a value of T, which is found looking at the t table, with 13 degrees of freedom(y-axis) and a confidence level of $1 - \frac{1 - 0.9}{2} = 0.95$ . So we have T = 1.7709

The margin of error is:

$M = T\frac{s}{\sqrt{n}} = 1.7709\frac{40}{\sqrt{14}} = 18.93$

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

The margin of error for a 90% confidence interval when n = 14 is 18.93.

b) n = 28

27 df, T = 1.7033

$M = T\frac{s}{\sqrt{n}} = 1.7033\frac{40}{\sqrt{28}} = 12.88$

The margin of error for a 90% confidence interval when n=28 is 12.88.

c) The margin of error for a 90% confidence interval when n = 45 is

44 df, T = 1.6802

$M = T\frac{s}{\sqrt{n}} = 1.6802\frac{40}{\sqrt{45}} = 10.02$

The margin of error for a 90% confidence interval when n = 45 is 10.02.

3 0

2 years ago

Find five solutions for the linear equations 2x + y =5

kondaur [170]

Answer:

Step-by-step explanation:

x = 2, y = 1

x = 1, y = 3

x = 0, y = 5

x = -1, y = 7

x = -2, y = 9

Hope that helps!

-Sabrina

7 0

2 years ago

Lori can do 42 push-ups. This is ten less than twice the amount of push-ups her sister can do. How many push-ups can her sister

densk [106]

Her sister can do 16 push ups

5 0

2 years ago

Read 2 more answers

Who answers this correctly with explanation gets vevmo'd/pay pal 25 Any Links Will Be Reported.

Inga [223]

Answer:

the answer is C

hope this helps

have a good day :)

Step-by-step explanation:

4 0

2 years ago

A student's grade for the four quarters are 95, 83, 91, and 85. What does the student need to earn on the final exam to have an

gulaghasi [49]

Answer:

The least score the student can get is 71 to get an overall B average at the end of the year.

Step-by-step explanation:

Let the score she needs to get be = x

We now have to take the mean of all the five subjects (including x) and equate it to the least score she can have to get a B grade.

Let us take the least score the student needs to get a B grade to be 85

Mean of all 5 scores =

$\frac{95+83+91+85+x}{5}=85$

$\frac{354+x}{5} =85$

$354+x = 425$

$x = 71$

The least score the student can get is 71 to get an overall B average at the end of the year.

3 0

2 years ago