All categories

2 years ago

What is the population standard deviation of this data set?*

Mathematics

1 answer:

Minchanka [31]2 years ago

5 0

Answer:

C) 2

Step-by-step explanation:

step 1: Find mean of data set

2+4+4+5+7+8 = 30

30/6 = 5

Mean = 5

step 2: subtract each data value from the mean and square it

5-2 = 3; 3² = 9

5-4 = 1; 1² = 1

5-5 = 0; 0² = 0

5-7 = -2; (-2²) = 4

5-8 = -3; (-3²) = 9

Add the squared results:

9+1+1+0+4+9 = 24

Divide 24 by 6 to get the Variance of 4

Take the square root of the Variance to get the Standard Deviation

$\sqrt{4}$ = 2

You might be interested in

I don’t understand pls help

SIZIF [17.4K]

Answer:

one solution is the correct answer

3 0

2 years ago

. A box in a certain supply room contains four 40-W lightbulbs, five 60-W bulbs, and six 75-W bulbs. Suppose that three bulbs ar

yaroslaw [1]

Answer:

a) 59.34%

b) 44.82%

c) 26.37%

d) 4.19%

Step-by-step explanation:

(a)

There are in total 4+5+6 = 15 bulbs. If we want to select 3 randomly there are K ways of doing this, where K is the combination of 15 elements taken 3 at a time

$K=\binom{15}{3}=\frac{15!}{3!(15-3)!}=\frac{15!}{3!12!}=\frac{15.14.13}{6}=455$

As there are 9 non 75-W bulbs, by the fundamental rule of counting, there are 6*5*9 = 270 ways of selecting 3 bulbs with exactly two 75-W bulbs.

So, the probability of selecting exactly 2 bulbs of 75 W is

$\frac{270}{455}=0.5934=59.34\%$

(b)

The probability of selecting three 40-W bulbs is

$\frac{4*3*2}{455}=0.0527=5.27\%$

The probability of selecting three 60-W bulbs is

$\frac{5*4*3}{455}=0.1318=13.18\%$

The probability of selecting three 75-W bulbs is

$\frac{6*5*4}{455}=0.2637=26.37\%$

Since the events are disjoint, the probability of taking 3 bulbs of the same kind is the sum 0.0527+0.1318+0.2637 = 0.4482 = 44.82%

(c)

There are 6*5*4 ways of selecting one bulb of each type, so the probability of selecting 3 bulbs of each type is

$\frac{6*5*4}{455}=0.2637=26.37\%$

(d)

The probability that it is necessary to examine at least six bulbs until a 75-W bulb is found, supposing there is no replacement, is the same as the probability of taking 5 bulbs one after another without replacement and none of them is 75-W.

As there are 15 bulbs and 9 of them are not 75-W, the probability a non 75-W bulb is $\frac{9}{15}=0.6$