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oksano4ka [1.4K]
3 years ago
11

A set of test scores is normally distributed with a mean of 130 and a standard deviation of 30 What score is necessary to reach

the 75th percentile? Select the closest answer
Mathematics
1 answer:
nlexa [21]3 years ago
7 0

Answer:

A score of 150.25 is necessary to reach the 75th percentile.

Step-by-step explanation:

Problems of normal distributions 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.

A set of test scores is normally distributed with a mean of 130 and a standard deviation of 30.

This means that \mu = 130, \sigma = 30

What score is necessary to reach the 75th percentile?

This is X when Z has a pvalue of 0.75, so X when Z = 0.675.

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

0.675 = \frac{X - 130}{30}

X - 130 = 0.675*30

X = 150.25

A score of 150.25 is necessary to reach the 75th percentile.

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At the market, Ms. Winn bought 3/4 lb of grapes and 5/8 lb of cherries.
wolverine [178]

Answer:

Part a) Ms. Winn bought 12 oz of grapes

Part b) Ms. Winn bought 10 oz of cherries

Part c) Ms. Winn bought 2 oz more of grapes than cherries

Part d) Mr. Phillips bought 6 more ounces of fruit than Ms. Winn

Step-by-step explanation:

Part a) How many ounces of grapes did Ms. Winn buy?

Remember that

1\ lb=16\ oz

To convert lb to oz multiply by 16

we know that

Ms. Winn bought 3/4 lb of grapes

Convert lb to oz

Multiply by 16

\frac{3}{4}\ lb= \frac{3}{4}(16)=12\ oz

therefore

Ms. Winn bought 12 oz of grapes

Part b) How many ounces of cherries did Ms. Winn buy?

Remember that

1\ lb=16\ oz

To convert lb to oz multiply by 16

we know that

Ms. Winn bought 5/8 lb of cherries

Convert lb to oz

Multiply by 16

\frac{5}{8}\ lb= \frac{5}{8}(16)=10\ oz

therefore

Ms. Winn bought 10 oz of cherries

Part c) How many more ounces of grapes than cherries did Ms. Winn buy?

Subtract the ounces of cherries from the ounces of grapes

so

12\ oz-10\ oz=2\ oz

therefore

Ms. Winn bought 2 oz more of grapes than cherries

Part d) If Mr. Phillips bought 1 3/4 pounds of raspberries, who bought more fruit, Ms. Winn or Mr. Phillips? How many ounces more?

Remember that

1\ lb=16\ oz

To convert lb to oz multiply by 16

we know that

Mr. Phillips bought 1 3/4 pounds of raspberries

Convert mixed number to an improper fraction

1\frac{3}{4}\ lb=\frac{1*4+3}{4}=\frac{7}{4}\ lb

Convert lb to oz

Multiply by 16

\frac{7}{4}\ lb= \frac{7}{4}(16)=28\ oz

Remember that

Ms. Winn bought 12 oz of grapes and 10 oz of cherries

In total Ms. Winn bought

12 oz+10 oz=22 oz -----> total ounces of fruit

so

Mr. Phillips bought 28 oz of fruit

Ms. Winn bought 22 oz of fruit

28\ oz > 22\ oz

Find the difference

(28\ oz-22\ oz)=6\ oz

therefore

Mr. Phillips bought 6 more ounces of fruit than Ms. Winn

4 0
3 years ago
What is the value of x?
andrew11 [14]
Hope this will help you .

answer is 68

given than 2 sides are equal therefor 2 angles are also equal ,

so, angle 1 + angle2 + angleX = 180 [ASP]

2angle1 + angle X = 180
angle x = 150 - [56][2]
angle x = 180-112

ANGLE x = 68 DEGREE
MARK IT BRAINIEST IF IT WAS REALLY HELPFUL.
4 0
3 years ago
I really need the help please and thank you
eimsori [14]

Asnwer: C

-------------------------------------

3 0
3 years ago
Hey i really need help with this. thank you:))
balandron [24]

Given:

L=2\dfrac{1}{2} ft and W=3\dfrac{2}{5} ft.

P=2L+2W

To find:

The value of P.

Solution:

We have,

P=2L+2W

Substituting L=2\dfrac{1}{2} and W=3\dfrac{2}{5}, we get

P=2\times 2\dfrac{1}{2}+2\times 3\dfrac{2}{5}

P=2\times \dfrac{2(2)+1}{2}+2\times \dfrac{3(5)+2}{5}

P=2\times \dfrac{5}{2}+2\times \dfrac{17}{5}

P=5+\dfrac{34}{5}

Taking LCM, we get

P=\dfrac{5(5)+34}{5}

P=\dfrac{25+34}{5}

P=\dfrac{59}{5}

P=11\dfrac{4}{5}

Therefore, the value of P is 11\dfrac{4}{5} ft.

7 0
3 years ago
What's bigger 3/8 or 5/12
Tom [10]
3/8 = 0,375
5/12 = 0,416

5/12 is bigger
7 0
2 years ago
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