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777dan777 [17]
1 year ago
8

The scores on a statistics test had a mean of 81 and a standard deviation of 9. One student was absent on the test day, and his

score wasn’t included in the calculation. If his score of 84 was added to the distribution of scores, what would happen to the mean and standard deviation?.
Mathematics
1 answer:
Rama09 [41]1 year ago
8 0

Using the definitions of the mean and of the standard deviation of a data-set, we have that:

  • The mean would increase.
  • The standard deviation would remain constant.

<h3>What are the mean and the standard deviation of a data-set?</h3>

  • The mean of a data-set is given by the <u>sum of all values in the data-set, divided by the number of values</u>.
  • The standard deviation of a data-set is given by the <u>square root of the sum of the differences squared between each observation and the mean, divided by the number of values</u>.

When the measure of 84 is added to the data-set, we have that:

  • A measure greater than the mean is added, hence the mean would increase.
  • The difference squared between 84 and the mean of 81 is of 9, which is the same as the standard deviation, which would remain constant.

More can be learned about the mean and the standard deviation of a data-set at brainly.com/question/26941429

#SPJ1

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Find the roots of the quadratic equation w+w²/3=0​
Daniel [21]

I assume that the equation you mean is below:

\large \boxed{w +  \frac{ {w}^{2} }{3}  = 0}

To find roots for this equation, we have to get rid of the denominator. We can do by multiplying both sides by 3.

\large{w(3) +  \frac{ {w}^{2} }{3} (3) = 0(3)} \\  \large{3w +  {w}^{2}  = 0}

Factor w-term out (common factor)

\large{w(3 + w) = 0} \\  \large{w = 0 \:  \:  \:  or \:  \:  \: 3 + w = 0} \\  \large{w = 0, - 3}

Answer

  • The roots of quadratic equation are 0,-3
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3 years ago
find the equation of parabola when point of intersection of directrix and axis is at (0,4) and focus at (6,4) ​
Allushta [10]

Answer:

Find the coordinates of the point of intersection of the axis and the directrix of the parabola whose focus is (3,3) and directrix is 3x−4y=2. Find also the length of the latus-rectum.

Step-by-step explanation:

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3 years ago
Evaluate 3x(y+4) 3 x ( y + 4 ) when x = 2 and y = 6
Nutka1998 [239]

Answer:

3600

Step-by-step explanation:

3x(y+4) 3 x ( y + 4 ); x = 2 and y = 6

Evaluate the value

3(2)[(6) + 4] 3(2)[(6) + 4 ]

6 × 10 × 6 × 10

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<u>-TheUnknown</u><u>Scientist</u>

7 0
3 years ago
A population is normally distributed with µ = 100 and σ = 10. a sample of size 9 is selected. the probability that an individual
ASHA 777 [7]
A) The empirical rule tells you the probability of being within 1 standard deviation of the mean is 68%.

b) The probability that the sample mean falls within 3 standard deviations* of the mean is 99.7%.

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* The standard deviation of the sample mean is 1/√9 = 1/3 of the standard deviation of an individual sample. Hence the same limits (90-110) now cover 3 standard deviations of the sample mean.
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3 years ago
There are 7 brothers and 6 sisters. If all siblings sat in a row and the girls requested to be seated next to one another, how m
SashulF [63]
<h3>Answer: 29,030,400</h3>

==============================================================

Explanation:

Let's say the mother will temporarily take the place of all the sisters. Wherever the mother sits will represent the block of girls.

Taking out the 6 sisters and replacing them with the mother leads to 7+1 = 8 people in a line.

There are 8! = 8*7*6*5*4*3*2*1 = 40,320 different ways to arrange 8 people.

----------

Again, the mother's position is where the sisters block will go. So let's say the mother was in seat #2. This would mean one brother would take seat #1, and all of the sisters would take the next six seats, until we reach seat #7 is when another brother would take the next seat.

Within any given permutation (the 40320 mentioned), there are 6! = 6*5*4*3*2*1 = 720 different ways to arrange just the girls in that girls block/group.

All together, there are 40320*720 = 29,030,400 different ways to arrange the 13 siblings where all the girls are seated together.

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