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IceJOKER [234]
2 years ago
14

In all, 1000 students took a statistics exam worth 150 points. The first quartile (or Q1) for all 1000 scores is 90 points. Abou

t how many students had scores greater than 90 points?
Mathematics
2 answers:
nasty-shy [4]2 years ago
5 0

Answer:

i think 750

Step-by-step explanation:

Brums [2.3K]2 years ago
4 0

Answer:

The number of students who scored more than 90 points is 750.

Step-by-step explanation:

Quartiles are statistical measures that the divide the data into four groups.

The first quartile (Q₁) indicates that 25% of the observation are less than or equal to Q₁.

The second quartile (Q₂) indicates that 50% of the observation are less than or equal to Q₂.

The third quartile (Q₃) indicates that 75% of the observation are less than or equal to Q₃.

It is provided that the first quartile is at 90 points.

That is, P (X ≤ 90) = 0.25.

The probability that a student scores more than 90 points is:

P (X > 90) = 1 - P (X ≤ 90)

                = 1 - 0.25

                = 0.75

The number of students who scored more than 90 points is: 1000 × 0.75 = 750.

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10-15. 5-9. 34-56 78-3

4 0
3 years ago
What is the area of a circle with diameter 8cm? Round your answer to the nearest tenth. use pi= 3.14
hodyreva [135]

Answer:

50.2 square cm

Step-by-step explanation:

Diameter = 8 cm

Radius = 8/2 = 4 cm

area \: of \: circle = \pi {r}^{2}  \\  = 3.14 \times  {4}^{2}  \\  = 3.14 \times 16 \\  = 50.24 \:  {cm}^{2}  \\  = 50.2 \:  {cm}^{2}

7 0
3 years ago
Read 2 more answers
Is that right? <br><br> Please help
kondaur [170]

Answer:

yes x = 16

Step-by-step explanation:

The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles, that is

133 = x + 117 ( subtract 117 from both sides )

16 = x

8 0
3 years ago
The number of major earthquakes in a year is approximately normally distributed with a mean of 20.8 and a standard deviation of
SCORPION-xisa [38]

Answer:

a) 51.60% probability that in a given year there will be less than 21 earthquakes.

b) 49.35% probability that in a given year there will be between 18 and 23 earthquakes.

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the zscore of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

\mu = 20.8, \sigma = 4.5

a) Find the probability that in a given year there will be less than 21 earthquakes.

This is the pvalue of Z when X = 21. So

Z = \frac{X - \mu}{\sigma}

Z = \frac{21 - 20.8}{4.5}

Z = 0.04

Z = 0.04 has a pvalue of 0.5160.

So there is a 51.60% probability that in a given year there will be less than 21 earthquakes.

b) Find the probability that in a given year there will be between 18 and 23 earthquakes.

This is the pvalue of Z when X = 23 subtracted by the pvalue of Z when X = 18. So:

X = 23

Z = \frac{X - \mu}{\sigma}

Z = \frac{23 - 20.8}{4.5}

Z = 0.71

Z = 0.71 has a pvalue of 0.7611

X = 18

Z = \frac{X - \mu}{\sigma}

Z = \frac{18 - 20.8}{4.5}

Z = -0.62

Z = -0.62 has a pvalue of 0.2676

So there is a 0.7611 - 0.2676 = 0.4935 = 49.35% probability that in a given year there will be between 18 and 23 earthquakes.

5 0
3 years ago
Solve the quadratic equation for x.<br><br> 3x2+12x=0<br> x = <br> or x =
Dmitry_Shevchenko [17]

Answer:

x=0, x=-4

Step-by-step explanation:

3 0
3 years ago
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