Remember, to find the mean of some scores, you must add all the scores together, then you must divide by the number of scores you added. In this case, you would divide by four, because you had four numbers you added to gether.

4 0

2 years ago

A’s DJ service charges a $200 setup fee and $75 an hour after that.

Bogdan [553]

The total cost includes the setup cost + per hour cost.

Let, x represents the time and y represents the total cost.

$y=200+75x$ .... (1)

Let Y represent the cost for B's DJ service.

$y=125x$ .... (2)

a. Graphing both the equations give the intersection point (solution) as (4,500)

It means for 4 hours, the total cost of both the DJ's is same at $500.

b. Substitution Method.

Plug y = 125x in equation (1)

$125x= 200+75x$

$125x-75x=200$

$50x=200$

$x=4$

$y=125\times 4 =500$

Hence, the total cost for 4 hours in both the service is $500.

c. Addition method.

Multiply equation (2) by -1

$-y = -125x$ .... Equation (3).

Add euation (1) and equation (3)

$y+(-y) = 200+75x-125x$

$0=200-50x$

$50x=200, x=4$

$y=500$

Solution: For x = 4, y = 500 ( same as the previous two methods)

For x = 2, equation (1)

$y=200+(75\times 2) = 350$

For x = 2, equation (2)

$y= 125\times 2 =250$

Hence, for 2 hours, DJ B would be a better choice since it would charge $250.

For x = 6 hours, equation (1)

$y=200+(75\times 6) =650$

For x= 6, equation (2)

$y=125\times 6=750$

For 6 hours, DJ A would be better option since it charges $650 for 6 hours.

8 0

3 years ago

A statistic is said to be unbiased if

xxMikexx [17]

Answer:

A statistic is said to be unbiased if the mean of its sampling distribution is equal to the true value of the parameter being estimated.

Step-by-step explanation:

A parameter is a number that describes the population.

A statistic is a number that describes a sample.

A statistic used to estimate a parameter is unbiased if the mean of its sampling distribution is exactly equal to the true value of the parameter being estimated. For example, the mean of a sample is an unbiased estimate of the mean of the population from which the sample was drawn.

A statistic is biased if its expected value is not equal to the parameter.

8 0

3 years ago