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4 years ago

Why aren't voluntary response samples usually representative of the population

Mathematics

2 answers:

klio [65]4 years ago

6 0

People who volunteer usually have a strong opinion so will not represent the opinion of the average person.

Answer: C

aivan3 [116]4 years ago

3 0

Answer:

C: the people who volunteer usually have a motive to do so and will be the only ones represented

Step-by-step explanation:

In a voluntary response sample, only people who are motivated to respond usually respond.

Since they are usually the only ones that respond, they are the only ones that will be represented.

You might be interested in

To drive to work, Dave has to drive 20 miles east and then 15 miles north. If there were a direct road going northeast, how many

suter [353]

By the Pythagorean theorem:

$x= \sqrt{20^2+15^2}= \sqrt{400+225}= \sqrt{625}=25 \ miles$

7 0

3 years ago

How to write an equation for the line perpendiculer and trhough the given ppoint?

valentinak56 [21]

A method that always works is to find the slope of the given line, then find the negative reciprocal of that. Your result will be the slope of the perpendicular line. Using this slope and the given point, fill in the parameters of the point-slope form of the equation of a line.

For m = slope of given line and (h, k) = given point, the perpendicular line will be
y = (-1/m)(x -h) +k

Often, this equation can be simplified to another appropriate form, such as slope-intercept form (y = mx+b) or standard form (ax+by=c).

_____
The slope of a given line can be found by solving its equation for y. The slope is the coefficient of x in that solution. If the given line is characterized by two points, (x1, y1) and (x2, y2), then its slope is m = (y2-y1)/(x2-x1).

In the unusual case where the given line is vertical (x=<some constant>), the slope of the perpendicular line is zero, and the line you want becomes y=k.

5 0

4 years ago

GreenBeam Ltd. claims that its compact fluorescent bulbs average no more than 3.24 mg of mercury. A sample of 25 bulbs shows a m

amm1812

Answer:

Null hypothesis: $\mu \leq 3.24$

Alternative hypothesis: $\mu > 3.24$

Step-by-step explanation:

1) Previous concepts and data given

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

A right tailed test (sometimes called an upper test) is when the alternative hypothesis statement contains a greater than (>) symbol.

$\bar X=3.29$ represent the sample mean

s represent the sample standard deviation

n represent the sample selected

$\alpha$ significance level

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean for fluorescent bulbs is no more than 3.24 mg of mercury, the system of hypothesis would be:

Null hypothesis: $\mu \leq 3.24$

Alternative hypothesis: $\mu > 3.24$

IIf we know the population deviation we can apply a z test to compare the actual mean to the reference value, and the statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

3 0

4 years ago

Use the Distributive Property to write each expression as an equivalent algebraic expression. (7 + a)3 Question 4 options: 3(7a)

AysviL [449]

Answer:

(B)21+3a

Step-by-step explanation:

An expression is said to be distributive when:

$(a+b)c=a \cdot c+b \cdot c$