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2 years ago

7

The results of a random survey show that 40 out of 75 people plan to vote for Mr.beston for a position on the local school board

. Which is the best prediction of the number of people who will vote for Mr.beston if 3,000 people vote

1 answer:

Sedaia [141]2 years ago

7 0

Answer:

1,600

Step-by-step explanation:

3000/75=40

40*40=1,600

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The amount of time all students in a very large undergraduate statistics course take to complete an examination is distributed c

Anestetic [448]

Answer:

a) The mean is $\mu = 60$

b) The standard deviation is $\sigma = 9$

Step-by-step explanation:

Normal Probability Distribution:

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.

The probability a student selected at random takes at least 55.50 minutes to complete the examination equals 0.6915.

This means that when X = 55.5, Z has a pvalue of 1 - 0.6915 = 0.3085. This means that when $X = 55.5, Z = -0.5$

So

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

$-0.5 = \frac{55.5 - \mu}{\sigma}$

$-0.5\sigma = 55.5 - \mu$

$\mu = 55.5 + 0.5\sigma$

The probability a student selected at random takes no more than 71.52 minutes to complete the examination equals 0.8997.

This means that when X = 71.52, Z has a pvalue of 0.8997. This means that when $X = 71.52, Z = 1.28$

So

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

$1.28 = \frac{71.52 - \mu}{\sigma}$

$1.28\sigma = 71.52 - \mu$

$\mu = 71.52 - 1.28\sigma$

Since we also have that $\mu = 55.5 + 0.5\sigma$

$55.5 + 0.5\sigma = 71.52 - 1.28\sigma$

$1.78\sigma = 71.52 - 55.5$

$\sigma = \frac{(71.52 - 55.5)}{1.78}$

$\sigma = 9$

$\mu = 55.5 + 0.5\sigma = 55.5 + 0.5*9 = 55.5 + 4.5 = 60$

Question

The mean is $\mu = 60$

The standard deviation is $\sigma = 9$

6 0

2 years ago

I have 1/3 of a pie. You have 1/3 of a pie. Add the pieces of pie together. How much pie do we have?

aliya0001 [1]

Answer:

2/3

Step-by-step explanation:

To add fractions add the numbers on top to each other and leave the bottom numbers alone if they are the same number.

$\frac{1}{3}+\frac{1}{3}=\frac{1+1}{3}=\frac{2}{3}$

8 0

2 years ago

Chips suppose a computer chip manufacturer rejects 2% of the chips produced because they fail presale testing.

Artyom0805 [142]

(a) P( fifth one is bad) = P( first 4 are OK) * P(5th is bad)

= (0.98)^4 * 0.02 = 0.0184 or 1.84%

(b) this will be (0.98)^10 = 81.70%

4 0

3 years ago

Graph y = -3.2 + 9. Then identify the x-intercept.

Nataly [62]

Answer:

9

Step-by-step explanation:

if you mean -3.2x+9 then the answer is 9 because you plug in 0 into x and solve the equation, you get the x intercept

7 0

3 years ago

A 2-gallon container of laundry detergent costs $19.68. what is the price per pint?

BigorU [14]

Answer:

0.81

Step-by-step explanation:

There are 8 pints = 1 gallon

8 times 2= 16/19.68=0.813

each pint is 0.81 cents

6 0

3 years ago