Nicola is multiplying 1/6 by 4/2

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

7) Which statement about perpendicular lines is true?

agasfer [191]

Answer:

is the a. Perpendicular lines form 90° angles.

3 0

2 years ago

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Danielle found an outfit she liked at two different stores. Store 1 marked the outfit down by 15%. They then marked down the red

guajiro [1.7K]

Answer: Store 2

Step-by-step explanation: sorry I don’t know how to explain.

6 0

3 years ago

Two cyclists start at the same point and travel in opposite directions. One cyclist travels 4 km per hour faster than the other.

yaroslaw [1]

Answer:

the rate of the first cyclist: 28km/h

the rate of the 2nd cyclist 28+4= 32km/h

Step-by-step explanation:

x= the rate of the first cyclist

x+4= the rate of the 2nd cyclist

after 4 hours: + the first cyclist travels 4x (km)

+ the 2nd cyclist travels 4(x+4) (km)

because the two cyclists are 240 km apart after 4 hours

=> 4x + 4(x+4) = 240 => x= 28

i hope it's useful forr u =)))

5 0

2 years ago

20 - 4 { 20÷ 7 ( 7 - 3 )}

hodyreva [135]

20 -4 { 20÷ 7 ( 7 - 3 )}

20 -4 { 20 ÷ 7 * 4 }

20 - 4 { 2.85 * 4 }

16 * 11.42

182.85

4 0

2 years ago

Read 2 more answers