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3 years ago

6

Matilda asked 20 random people in the street if they would like to discuss what they want to do during the summer break. Seven o

f them said yes.
How is this sample biased?

(1)She should have asked more people.
(2)The people who chose to participate might not be similar to the people who didn’t.
(3)The number of people who agreed was too small.
(4)She should have asked girls only.

2 answers:

ArbitrLikvidat [17]3 years ago

5 0

I think option two is the correct one, because 1 and two contradict eachother and 4 doesn't make sense

netineya [11]3 years ago

5 0

Answer:I know the answer is not number one I choose it and it was wrong

Step-by-step explanation:

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Solve for y: 10.3 = 0.6y

Mademuasel [1]

Y is being multiplied by 0.6 so you have to divide by 0.6 on both sides to leave y alone.
y=10.3/0.6

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3 years ago

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For the equations given below, which statement is true?

allochka39001 [22]

Answer: C. The equations have the same solution because the second equation can be obtained by adding 6 to both sides of the first equation.

Step-by-step explanation:

You know that the first equation is:

$-3x-8=19$

And the second equation is:

$-3x-2=25$

According to the Addition property of equality:

If $a=b$ ; then $a+c=b+c$

Then, you can add 6 to both sides of the first equation to keep it balanced. Then, you get:

$-3x-8=19\\\\-3x-8+(6)=19+(6)$

$-3x-2=25$

Therefore, you can observe that the second equation can be obtained by adding 6 to both sides of the first equation, therefore, the equations have the same solution.

If you want to verify this, you can solve for "x" from both equations:

- First equation:

$-3x-8=19\\\\-3x=19+8\\\\x=\frac{27}{-3}\\\\x=-9$

- Second equation:

$-3x-2=25\\\\-3x=25+2\\\\x=\frac{27}{-3}\\\\x=-9$

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3 years ago

Can someone help me this is due soon

Hatshy [7]

Answer:

30

Step-by-step explanation:

3 + 8 + 7 + 2 + 6 + 4 = 30

<em>good luck, i hope this helps :)</em>

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2 years ago

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A bag contains 4 blue marbles and 2 yellow marbles. Two marbles are randomly chosen (the first marble is NOT replaced before dra

VMariaS [17]

Answer:

0.4 = 40% probability that both marbles are blue.

0.0667 = 6.67% probability that both marbles are yellow.

53.33% probability of one blue and then one yellow

If you are told that both selected marbles are the same color, 0.8571 = 85.71% probability that both are blue

Step-by-step explanation:

To solve this question, we need to understand conditional probability(for the final question) and the hypergeometric distribution(for the first three, because the balls are chosen without being replaced).

Hypergeometric distribution:

The probability of x sucesses is given by the following formula:

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}$

In which:

x is the number of sucesses.

N is the size of the population.

n is the size of the sample.

k is the total number of desired outcomes.

Combinations formula:

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

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

Conditional Probability

We use the conditional probability formula to solve this question. It is

$P(B|A) = \frac{P(A \cap B)}{P(A)}$

In which

P(B|A) is the probability of event B happening, given that A happened.

$P(A \cap B)$ is the probability of both A and B happening.

P(A) is the probability of A happening.

What is the probability that both marbles are blue?

4 + 2 = 6 total marbles, which means that $N = 6$

4 blue, which means that $k = 4$

Sample of 2, which means that $n = 2$

This is P(X = 2). So

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}$

$P(X = 2) = h(2,6,2,4) = \frac{C_{4,2}*C_{2,0}}{C_{6,2}} = 0.4$

0.4 = 40% probability that both marbles are blue

What is the probability that both marbles are yellow?

4 + 2 = 6 total marbles, which means that $N = 6$

2 yellow, which means that $k = 2$

Sample of 2, which means that $n = 2$

This is P(X = 2). So

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}$

$P(X = 2) = h(2,6,2,2) = \frac{C_{2,2}*C_{4,0}}{C_{6,2}} = 0.0667$

0.0667 = 6.67% probability that both marbles are yellow.

What is the probability of one blue and then one yellow?

Total is 100%.

Can be:

Both blue(40%)

Both yellow(6.67%)

One blue and one yellow(x%). So

40 + 6.67 + x = 100

x = 100 - 46.67

x = 53.33

53.33% probability of one blue and then one yellow.

If you are told that both selected marbles are the same color, what is the probability that both are blue?

Conditional probability.

Event A: Both same color

Event B: Both blue

Probability of both being same color:

Both blue(40%)

Both yellow(6.67%)

This means that $P(A) = 0.4 + 0.0667 = 0.4667$

Probability of both being the same color and blue:

40% probability that both are blue, which means that $P(A \cap B) = 0.4$

Desired probability:

$P(B|A) = \frac{P(A \cap B)}{P(A)} = \frac{0.4}{0.4667} = 0.8571$

If you are told that both selected marbles are the same color, 0.8571 = 85.71% probability that both are blue

8 0

3 years ago

Find the value of X?

Molodets [167]

Answer:

x = 58

Step-by-step explanation:

The exterior angle is equal to the sum of the opposite interior angles

90 = 32+x

Subtract 32 from each side

90-32 = x

58 =x

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3 years ago