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3 years ago

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Since the sample size is always smaller than the size of the population, the sample mean a. must be larger than the population m

ean b. can be smaller, larger, or equal to the population mean c. must be equal to the population mean d. must always be smaller than the population mean

1 answer:

Stels [109]3 years ago

7 0

The answer is;

B. Can Be Smaller, Larger, Or Equal To The Population Mean

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7.109) The leading brand of dishwasher detergent has a 30% market share. A sample of 25 dishwasher detergent customers was taken

Rina8888 [55]

Answer:

0.9021 = 90.21% probability that 10 or fewer customers choose the leading brand

Step-by-step explanation:

For each customer, there are only two possible outcomes. Either they choose the leading brand, or they do not. The probability of a customer choosing the leading brand is independent of any other customer, which means that the binomial probability distribution is used to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

The leading brand of dishwasher detergent has a 30% market share.

This means that $p = 0.3$

A sample of 25 dishwasher detergent customers was taken.

This means that $n = 25$

a. What is the probability that 10 or fewer customers choose the leading brand?

This is:

$P(X \leq 10) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) + P(X = 9) + P(X = 10)$

In which

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 0) = C_{25,0}.(0.3)^{0}.(0.7)^{25} = 0.0001$

$P(X = 1) = C_{25,1}.(0.3)^{1}.(0.7)^{24} = 0.0014$

$P(X = 2) = C_{25,2}.(0.3)^{2}.(0.7)^{23} = 0.0074$

$P(X = 3) = C_{25,3}.(0.3)^{3}.(0.7)^{22} = 0.0243$

$P(X = 4) = C_{25,4}.(0.3)^{4}.(0.7)^{21} = 0.0572$

$P(X = 5) = C_{25,5}.(0.3)^{5}.(0.7)^{20} = 0.1030$

$P(X = 6) = C_{25,6}.(0.3)^{6}.(0.7)^{19} = 0.1472$

$P(X = 7) = C_{25,7}.(0.3)^{7}.(0.7)^{18} = 0.1712$

$P(X = 8) = C_{25,8}.(0.3)^{8}.(0.7)^{17} = 0.1651$

$P(X = 9) = C_{25,9}.(0.3)^{9}.(0.7)^{16} = 0.1336$

$P(X = 10) = C_{25,10}.(0.3)^{10}.(0.7)^{15} = 0.0916$

Then

$P(X \leq 10) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) + P(X = 6) + P(X = 7) + P(X = 8) + P(X = 9) + P(X = 10) = 0.0001 + 0.0014 + 0.0074 + 0.0243 + 0.0572 + 0.1030 + 0.1472 + 0.1712 + 0.1651 + 0.1336 + 0.0916 = 0.9021$

0.9021 = 90.21% probability that 10 or fewer customers choose the leading brand

3 0

3 years ago

Please solve with explanation (high points)

IgorLugansk [536]

So, we know that:

$A=\dfrac{1}{2}ab\\P=a+b+c\\a^2+b^2=c^2$

We also know that $(a+b)^2=a^2+2ab+b^2$ . We will use that fact to find $c$ in terms of $A$ and $P$ .

$A=\dfrac{1}{2}ab\Rightarrow 2ab=4A\\P=a+b+c\Rightarrow a+b=P-c$

Therefore:

$(P-c)^2=c^2+4A\\P^2-2cP+c^2=c^2+4a\\2cP=P^2-4A\\c=\dfrac{P^2-4A}{2P}$

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2 years ago

What is the value of X?

andrezito [222]

Solution:

<u>Note that:</u>

3x + 50 = 6x - 10 (Vertically opposite angles)

Simplify the equation to find x.

<u>Add 10 both sides.</u>

3x + 50 = 6x - 10
=> 3x + 50 + 10 = 6x - 10 + 10
=> 3x + 60 = 6x

<u>Subtract 3x both sides.</u>

3x + 60 = 6x
=> 3x - 3x + 60 = 6x - 3x
=> 60 = 3x

<u>Divide 3 both sides.</u>

60 = 3x
=> 60/3 = 3x/3
=> x = 20

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3 years ago

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Five times a number is 120, what is the number

Mandarinka [93]

24
Explanation: 24x5 = 120

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On a certain hot summer's day, 769 people used the public swimming pool. The daily prices are $1.25 for children and $2.50 for

pickupchik [31]

579 adults and 190 children I’m pretty sure this is right

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3 years ago