Mathematics, 13.03.2020 05:43 smithad382

48. Reading Rates The reading speed of sixth-grade students is approximately normal, with a mean speed of 125 words per minute and a standard deviation of 24 words per minute. (a) What is the reading speed of a sixth-grader whose reading speed is at the 90th percentile

Answers: 3

Show answers

Answers

Answer from: tylermdons

The reading speed of a sixth-grader whose reading speed is at the 90th percentile is 155.72 words per minute.

Step-by-step explanation:

Problems of normally distributed samples are 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:

$\mu = 125, \sigma = 24$

What is the reading speed of a sixth-grader whose reading speed is at the 90th percentile

This is the value of X when Z has a pvalue of 0.9. So it is X when Z = 1.28.

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

$1.28 = \frac{X - 125}{24}$

X - 125 = 1.28*24

X = 155.72

The reading speed of a sixth-grader whose reading speed is at the 90th percentile is 155.72 words per minute.

Answer from: Gbecky122

the reading speed of a sixth-grader whose reading speed is at the 90th percentile is 155.84 per minute

Step-by-step explanation:

Since the the reading speed of sixth-grade students is approximately normal, we would apply the formula for normal distribution which is expressed as

z = (x - µ)/σ

Where

x = reading speed

µ = mean speed

σ = standard deviation

From the information given,

µ = 125 words per minute

σ = 24 words per minute

Looking at the normal distribution table, the z value corresponding to the 90th percentile(0.9), is 1.285

Therefore,

1.285 = (x - 125)/24

24 × 1.285 = x - 125

30.84 = x - 125

x = 125 + 30.84

x = 155.84

Answer from: Quest

asdsaddsa

step-by-step explanation:

Answer from: Quest

in if you ask questions, the points are taken from your total and given to the one who answered it..

so if i have 30 points and i ask a question for 5 points, then when someone asks a question i will lose 5 points and the answerer earns 5

happy to

Another question on Mathematics

Mathematics, 21.06.2019 12:30

The polynomial function of least degree with a leading coefficient of 1 is: f(x) = x3 + ax2 + bx + c

Answers: 1

Answer

Mathematics, 21.06.2019 17:00

Tim's phone service charges $23.06 plus an additional $0.22 for each text message sent per month. if tim's phone bill was $28.56, which equation could be used to find how many text messages, x, tim sent last month?

Answers: 2

Answer

Mathematics, 21.06.2019 19:30

Tim's phone service charges $26.39 plus an additional $0.21 for each text message sent per month. if tim's phone bill was $31.64, which equation could be used to find how many text messages, x, tim sent last month?

Answers: 1

Answer

Mathematics, 21.06.2019 21:00

The ph level of a blueberry is 3.1 what is the hydrogen-ion concentration [h+] for the blueberry

Answers: 2

Answer

You know the right answer?

48. Reading Rates The reading speed of sixth-grade students is approximately normal, with a mean spe...

Questions