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2 years ago

Evaluate each expression -5x8+12

Mathematics

1 answer:

Oksanka [162]2 years ago

4 0

-28 because using PEMDAS you would do -5x8 which =-40 plus 12 is -28

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Calculate the sample standard deviation and sample variance for the following frequency distribution of hourly wages for a sampl

lidiya [134]

Answer:

(a) The sample variance is 16.51

(a) The sample standard deviation is 4.06

Step-by-step explanation:

Given

$\begin{array}{cc}{Class} & {Frequency} & 8.26 - 10.00 & 20 &10.01-11.75 & 38 &11.76 - 13.50& 36 & 13.51-15.25 &25&15.26-17.00 &27 &\ \end{array}$

Solving (a); The sample variance.

First, calculate the class midpoints.

This is the mean of the intervals.

i.e.

$x_1 = \frac{8.26+10.00}{2} = \frac{18.26}{2} = 9.13$

$x_2 = \frac{10.01+11.75}{2} = \frac{21.76}{2} = 10.88$

$x_3 = \frac{11.76+13.50}{2} = \frac{25.26}{2} = 12.63$

$x_4 = \frac{13.51+15.25}{2} = \frac{28.76}{2} = 14.38$

$x_5 = \frac{15.26+17.00}{2} = \frac{32.26}{2} = 16.13$

So, the table becomes:

$\begin{array}{ccc}{Class} & {Frequency} & {x} & 8.26 - 10.00 & 20&9.13 &10.01-11.75 & 38 &10.88&11.76 - 13.50& 36 &12.63& 13.51-15.25 &25&14.38&15.26-17.00 &27 &16.13\ \end{array}$

Next, calculate the mean

$\bar x = \frac{\sum fx}{\sum f}$

$\bar x = \frac{20*9.13 + 38 * 10.88+36*12.63+25*14.38+27*16.13}{20+38+36+25+27}$

$\bar x = \frac{1845.73}{146}$

$\bar x = 12.64$

Next, the sample variance is:

$\sigma^2 = \frac{\sum f(x - \bar x)^2}{\sum f - 1}$

So, we have:

$\sigma^2 = \frac{20*(9.13-12.63)^2 + 38 * (10.88-12.63)^2 +...........+27 * (16.13 -12.63)^2}{20+38+36+25+27-1}$

$\sigma^2 = \frac{2393.6875}{145}$

$\sigma^2 = 16.51$

The sample standard deviation is:

$\sigma = \sqrt{\sigma^2}$

$\sigma = \sqrt{16.51}$

$\sigma = 4.06$

6 0

2 years ago

Theresa bought three containers of tennis balls at $2.98 each. She had a coupon for $1 off. Her mom paid for half of the remaini

Rzqust [24]

Answer:

$3.97

Step-by-step explanation:

Three containers @$2.98 = 3 × 2.98 = $8.94

Less $1 = -1.00

7.94

Less 50% paid my mom = ½ × 7.94 = -3.97

Paid by Theresa = $3.97

[(3 × 2.98) - 1] ÷ 2 = (8.94 - 1) ÷ 2 = 7.94 ÷ 2 = 3.97

6 0

2 years ago

H = {(2, 5), (3, 5), (4, 5), (5, 5), (6, 5)} Is H a function and why?

Lorico [155]

Answer:

h is a function

Step-by-step explanation:i know that h is a function i just dont know why

7 0

3 years ago

Answer -7 x (-9) = ? Thank You!

artcher [175]

-7 x (-9) = +63

because if we multiply negative by negative we obtain +

5 0

3 years ago

I need help!!! :))))

timurjin [86]

Answer:

Step-by-step explanation:

6 0

2 years ago

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