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igomit [66]
3 years ago
13

A bag contains 100 marbles, some red and some purple. Suppose a student, without looking, chooses a marble out of the bag, recor

ds the color, and then places that marble back in the bag. The student has recorded 9 red marbles and 11 purple marbles. Using these results, predict the number of red marbles in the bag.​
Mathematics
1 answer:
LUCKY_DIMON [66]3 years ago
8 0

Answer:

45

Step-by-step explanation:

9 of the 20 drawn were red

9/20 * 100 = 45

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Suppose a random sample of 100 observations from a binomial population gives a value of pˆ = .63 and you wish to test the null h
irakobra [83]

Answer:

We conclude that the population proportion is equal to 0.70.

Step-by-step explanation:

We are given that a random sample of 100 observations from a binomial population gives a value of pˆ = 0.63 and you wish to test the null hypothesis that the population parameter p is equal to 0.70 against the alternative hypothesis that p is less than 0.70.

Let p = <u><em>population proportion.</em></u>

(1) The intuition tells us that the population parameter p may be less than 0.70 as the sample proportion comes out to be less than 0.70 and also the sample is large enough.

(2) So, Null Hypothesis, H_0 : p = 0.70      {means that the population proportion is equal to 0.70}

Alternate Hypothesis, H_A : p < 0.70      {means that the population proportion is less than 0.70}

The test statistics that would be used here <u>One-sample z-test</u> for proportions;

                           T.S. =  \frac{\hat p-p}{\sqrt{\frac{p(1-p)}{n} } }  ~  N(0,1)

where, \hat p = sample proportion = 0.63

            n = sample of observations = 100

So, <u><em>the test statistics</em></u>  =  \frac{0.63-0.70}{\sqrt{\frac{0.70(1-0.70)}{100} } }

                                     =  -1.528

The value of z-test statistics is -1.528.

<u>Now at 0.05 level of significance, the z table gives a critical value of -1.645 for the left-tailed test.</u>

Since our test statistics is more than the critical value of z as -1.528 > -1.645, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region due to which <u><em>we fail to reject our null hypothesis</em></u>.

Therefore, we conclude that the population proportion is equal to 0.70.

(c) The observed level of significance in part B is 0.05 on the basis of which we find our critical value of z.

4 0
3 years ago
Sophia uses 18 beads to make a necklace. Three sixths of the beads are purple. How many beads are purple?
joja [24]

Answer:

9 beads are purple

Step-by-step explanation:

we know that

To find out how many  beads are purple, multiply the total beads by the fraction of the beads that are purple

so

18(\frac{3}{6})=9\ beads

therefore

9 beads are purple

Another way to solve the problem is convert the fraction in percentage

we have

\frac{3}{6}=\frac{1}{2}=0.50*100=50\%

so

If the total are 18 beads

50% is 9 beads

therefore

9 beads are purple

8 0
3 years ago
PLEASE HELP YOU CAN HAVE BRAINLIEST!!!
Katen [24]

Answer: 4

Step-by-step explanation:

6 0
2 years ago
M∠DEF = __because they are_________
vovikov84 [41]

Answer:

m∠GDE

alternate interior angles

3 0
3 years ago
2 (c+7)=2c+14 is an example of an
horrorfan [7]
The given mathematical expression <span>2 (c+7)=2c+14 is an example is</span> an example of Distributive Property.
We can examine the given problem, we have 2(c+7) where 2 can be distributed to both c and 7. Then the result of distribution is 2c and 14 which the same in the opposite side.
8 0
3 years ago
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