Which set of absolute values is compared correctly? A. |-7| |-5| > |-7| > |-8| D. |-4| > |9| > |-3|

The mean points obtained in an aptitude examination is 159 points with a standard deviation of 13 points. What is the probabilit

Korolek [52]

Answer:

0.4514 = 45.14% probability that the mean of the sample would differ from the population mean by less than 1 point if 60 exams are sampled

Step-by-step explanation:

To solve this question, we have to understand the normal probability distribution and the central limit theorem.

Normal probability distribution:

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.

Central limit theorem:

The Central Limit Theorem estabilishes that, for a random variable X, with mean $\mu$ and standard deviation $\sigma$ , a large sample size can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$

In this problem, we have that:

$\mu = 159, \sigma = 13, n = 60, s = \frac{13}{\sqrt{60}} = 1.68$

What is the probability that the mean of the sample would differ from the population mean by less than 1 point if 60 exams are sampled?

This is the pvalue of Z when X = 159+1 = 160 subtracted by the pvalue of Z when X = 159-1 = 158. So

X = 160

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

By the Central Limit Theorem

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

$Z = \frac{160 - 159}{1.68}$

$Z = 0.6$

$Z = 0.6$ has a pvalue of 0.7257

X = 150

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

$Z = \frac{158 - 159}{1.68}$

$Z = -0.6$

$Z = -0.6$ has a pvalue of 0.2743

0.7257 - 0.2743 = 0.4514

0.4514 = 45.14% probability that the mean of the sample would differ from the population mean by less than 1 point if 60 exams are sampled

7 0

3 years ago

x2 – 144 = 0 (what formula did you use besides calculator or quadratic formula ) show work on how you solved plz :D (put down 26

SVEN [57.7K]

2X - 144 = 0
+ 144. + 144
2X = 144
/2. /2.
X = 72

3 0

2 years ago

Read 2 more answers

1. What is the probability of getting a number greater than 2 on two rolls of a six-sided die both times?

prisoha [69]

Answer:

For this question, the options are written the wrong way. In each of the answers below, the correct form of the question will be added.

The answers are:

1. e) 4/9

2. a) 1/16

3. 980 girls

4. c) 2/3

5. d) 1/13

6. a) 42 boys

7. d) 1/21

8. b) 1/6

Step-by-step explanation:

1. What is the probability of getting a number greater than 2 on two rolls of a six-sided die both times?

a) 4/3

b) 2/6

c) 4/6

d) 3/6

e) 4/9

The correct answer is e) 4/9 because the probability of getting a number greater than 2 in two rolls is 4/6 * 4/6 =16/36 = 4/9

2. A fair coin is tossed four times. What is the probability that it will be heads every time?

a) 1/16

b) 4/2

c) 2

d) 4/16

e) 1

The correct answer is a) 1/16 because the probability of each time that the coin is tossed is 1/2, and for 4 tosses is 1/2*1/2*1/2*1/2 = 1/16

3. The ratio of the number of girls to the number of boys was 2 to 5. If 2,450 students were present, how many were girls and how many were boys?

The correct answer is 980 girls, because 2450*2/5 = 980

4. A die is rolled twice. What is the probability of rolling a 5 or getting an even number?

a) 3/1

b) 1/12

c) 2/3

d) 1/3

If the die is rolled twice there are 12 possible outcomes and 8 of those outcomes can be 5 or an even number. The probability is 8/12 = 2/3

5. If one card is drawn from a standard deck, what is the probability of getting a jack?

a) 4/13

b) 1/52

c) 52

d) 1/13

e) 4

In a standard deck, there are 13 jack cards, the probability of getting a jack the first time is 1/13

6. There are 210 boys trying out for football. If 20% made the team, how many were chosen?

a) 42

b) 10

c) 4200

d) 105

e) 20

The number of boys that will be picked for the team is 210*20% = 42

7. From 42 boys who made the team, one will be chosen as kicker and one will be chosen as quarterback. What is the probability of being chosen as the kicker or the quarterback?

a) 2/21

b) 1/42

c) 2

d) 1/21

e) 42

The probability of getting picked for one of the 2 positions is 2/42 = 1/21

8. Two dice are rolled. There are 36 possible outcomes of rolling two dice. What is the probability of getting a total of seven on one roll?

a) 7

b) 1/6

c) 0

d) 7/36

e) 1/36

There are 6 ways of getting a sum of 7 tossing 2 dice, 1+6, 6+1, 2+5, 5+2, 3+4, 4+3. The probability is 6/36 = 1/6

3 0

3 years ago

PLEASE HELP ME ASAAAAAPPPPPPPPPPPP PLEASE HELP ME FAST What is 5 x 2/3 ? A) 3 1/3 B) 3 2/5 C) 5 2/3 D) 10/15

katrin2010 [14]

Answer:

A) 3 1/3

Step-by-step explanation:

5 x 2 = 10

10/3= 3 with a remainder of 1. That gives you 3 1/3

5 0

3 years ago

Read 2 more answers

Logan is going to invest $61,000 and leave it in an account for 20 years. Assuming

hodyreva [135]

Answer:

its 2.62

Step-by-step explanation:

6 0

3 years ago

Read 2 more answers

Which set of absolute values is compared correctly? A. |-7| |-5| > |-7| > |-8| D. |-4| > |9| > |-3| > |-10|