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3 years ago

13

claim: the mean pulse rate (in beats per minute) of adult males is equal to 69 bpm. for a random sample of 140 adult males,

the mean pulse rate is 70.4 bpm and the standard deviation is 11.1 bpm. find the value of the test statistic.

1 answer:

zaharov [31]3 years ago

8 0

Answer:

93.19%

Step-by-step explanation:

We have that the mean (m) is equal to 70.4, the standard deviation (sd) 11.1 and the sample size (n) = 140

They ask us for P (x =69)

For this, the first thing is to calculate z, which is given by the following equation:

z = (x - m) / (sd / (n ^ 1/2))

We have all these values, replacing we have:

z = (69 - 70.4) / (11.1 / (140 ^ (1/2)))

z = 1.49

With the normal distribution table (attached), we have that at that value, the probability is:

P (z <1.49) = 0.9319

The probability is 93.19%

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Suppose a student's score on a standardize test to be a continuous random variable whose distribution follows the Normal curve.

blsea [12.9K]

Answer:

a) Percentage of students scored below 300 is 1.79%.

b) Score puts someone in the 90th percentile is 638.

Step-by-step explanation:

Given : Suppose a student's score on a standardize test to be a continuous random variable whose distribution follows the Normal curve.

(a) If the average test score is 510 with a standard deviation of 100 points.

To find : What percentage of students scored below 300 ?

Solution :

Mean $\mu=510$ ,

Standard deviation $\sigma=100$

Sample mean $x=300$

Percentage of students scored below 300 is given by,

$P(Z\leq \frac{x-\mu}{\sigma})\times 100$

$=P(Z\leq \frac{300-510}{100})\times 100$

$=P(Z\leq \frac{-210}{100})\times 100$

$=P(Z\leq-2.1)\times 100$

$=0.0179\times 100$

$=1.79\%$

Percentage of students scored below 300 is 1.79%.

(b) What score puts someone in the 90th percentile?

90th percentile is such that,

$P(x\leq t)=0.90$

Now, $P(\frac{x-\mu}{\sigma} < \frac{t-\mu}{\sigma})=0.90$

$P(Z< \frac{t-\mu}{\sigma})=0.90$

$\frac{t-\mu}{\sigma}=1.28$

$\frac{t-510}{100}=1.28$

$t-510=128$

$t=128+510$

$t=638$

Score puts someone in the 90th percentile is 638.

5 0

4 years ago

If a figure is dilated by a scale factor less than one, does the shape get larger or smaller?

malfutka [58]

I think that it gets smaller. (not entirely sure)

6 0

3 years ago

Read 2 more answers

A deck of 38 cards contains 16 blue cards, 6 red cards, and 16 yellow cards. What is the probability of randomly drawing a blue

GalinKa [24]

The probability of drawing a blue card is equal to the quotient when the number of blue cards is divided by the total number of cards. This is, 16/38 which is also equal to 8/19. Thus, the probability of drawing a yellow card is 8/19. The answer is letter C.

5 0

3 years ago

Archy [21]

Answer:

Option 2 50 ≤ s ≤ 100

Option 5 She could deposit $50

Option 6 She could deposit $75

Step-by-step explanation:

Let

s -----> amount of money Layla deposit into a saving account

we know that

25%=25/100=0.25

50%=50/100=0.50

so

$s\geq 0.25*200$ -----> $s\geq \$50$

$s\leq 0.50*200$ -----> $s\leq \$100$

The compound inequality is

$\$50 \leq s\leq \$100$

<em>Verify each case</em>

case 1) 25 ≤ s ≤ 50

The statement is false

see the procedure

case 2) 50 ≤ s ≤ 100

<u>The statement is True</u>

see the procedure

case 3) s ≤ 25 or s ≥ 50

The statement is false

Because is s ≤ 100 and s ≥ 50

case 4) s ≤ 50 or s ≥ 100

The statement is false

Because is s ≤ 100 and s ≥ 50

case 5) She could deposit $50

<u>The statement is true</u>

Because the value of s satisfy the compound inequality $\$50 \leq s\leq \$100$

case 6) She could deposit $75

<u>The statement is true</u>

Because the value of s satisfy the compound inequality $\$50 \leq s\leq \$100$

3 0

4 years ago

Read 2 more answers

KX equals X +4 find K7

Andre45 [30]

KX = x+4 so solve for k.
Divide both sides of the equation by x and you get K=4.
Plug it in, and you get (4)(7)=28
Your answer is 28.

5 0

3 years ago