How many solutions does the following have?<br> 1x-5y=15<br> -1+5y=-15

Consider the accompanying data on flexural strength (MPa) for concrete beams of a certain type.

Leona [35]

Answer:

Step-by-step explanation:

Hello!

The variable of interest is X: flexural strength of concrete beams.

Data:

7.3 6.8 8.6 9.7 11.6 9.7 6.8 7.7 11.8 7.4 8.1 8.7 6.3 7.9 7.0 7.9 7.8 6.5 6.3 7.0 7.5 7.7 7.2 11.3 9.0 10.7 5.1

a.

The point estimate of the mean value is the sample mean. You calculate it using the following formula:

X[bar]= ∑X/n= 219.40/27= 8.1259≅ 8.13

b)x

b.

The point estimate that divides the sample in 50%-50% is the measure of central tendency called Median(Me).

To reach the median you have to calculate it's position (PosMe)

For uneven samples PosMe= (n+1)/2= (27+1)/2= 14 ⇒ This means that the Median is the 14th observation of the data set.

So next is to order the data from lower to heighest and identify the value in the 14th position:

5,1 ; 6,3; 6,3; 6,5 ; 6,8; 6,8; 7; 7; 7,2; 7,3; 7,4 ; 7,5 ; 7,7 ; 7,7 ; 7,8 ; 7,9 ; 7,9 ; 8,1 ; 8,6 ; 8,7 ; 9 ; 9,7 ; 9,7 ; 10,7 ; 11,3 ; 11,6 ; 11,8

Me= 7.7

d) x tilde

c.

The point estimate of the population standard deviation is the sample standard deviation. The standard deviation is the square root of the variance, so the first step is to calculate the sample variance:

$S^2= \frac{1}{n-1}*[sumX^2-\frac{(sumX)^2}{n} ]$

∑X²= 1858.92

$S^2= \frac{1}{26}*[1858.92-\frac{219.40^2}{27} ] = 2.926$

S= √2.926= 1.71

The standard deviation is a measurement of variability, it shows how to disperse the data is concerning the sample mean.

d. This estimate describes the spread of the data.

I hope it helps!

7 0

3 years ago

Ms. Watts is a famous motivational speaker. She travels across the country by jet and gives an average of ten presentations a we

expeople1 [14]

Answer:

5 weeks

Step-by-step explanation:

We are told that the auditorium holds an average of 1000 people each.

And that she charges $40 each.

Thus;

Total income for each speech is;

1000 × 40 = $40000

Since she gives an average of 10 presentations each week.

Total income per week = 10 × 40000 = $400,000

Now,the expenses she makes for each speech weekly is;

Renting auditorium = $15000

Motel, jet expenses, support personnel = $75000

Thus,

Total expenses per week = 15000 + 75000 = $90000

Now, total profit per week is;

P_weekly = Total income per week - Total expenses per week

P_weekly = $400000 - $90000

P_weekly = $310000

There are 52 weeks in a year, thus, profit in a year is;

P_yearly = 52 × 310000 = $16120000

Now, we want to find out how long it took her to make $1,400,000 a year.

We know that;

$16120000 was achieved in 52 weeks

Thus;$1,400,000 will be achieved in;

(1400000 × 52)/16120000 = 4.52 weeks approximately 5 weeks.

4 0

3 years ago

Monthly spending : $46,$62,$63,$57,$50$42$56$40 its median, mode and range

ozzi

Mean = $52
median = $53
no mode
range = 63 - 40 = $23

6 0

2 years ago

In a survey of 2065 adults in a certain country conducted during a period of economic uncertainty, 63 % thought that wages paid

LenKa [72]

Answer:

a) D.The interpretation is flawed. No interval has been provided about the population proportion.

b) D.The interpretation is flawed. The interpretation indicates that the level of confidence is varying.

c) A.The interpretation is reasonable.

d) C.The interpretation is flawed. The interpretation suggests that this interval sets the standard for all the other intervals, which is not true.

Step-by-step explanation:

(a) We are 95 % confident 63 % of adults in the country during the period of economic uncertainty felt wages paid to workers in industry were too low. Is the interpretation reasonable?

D.The interpretation is flawed. No interval has been provided about the population proportion.

The sample proportion alone will not give us any confidence in estimating the true proportion of adults in the country during the period of economic uncertainty felt wages paid to workers in industry were too low.

We need a 95% confidence interval to claim that the true proportion is within this interval. In this case, as the margin of error is 4%, the 95% CI is 59% and 67%.

(b) We are 91 % to 99 % confident 63 % of adults in the country during the period of economic uncertainty felt wages paid to workers in industry were too low. Is the interpretation reasonable?

D.The interpretation is flawed. The interpretation indicates that the level of confidence is varying.

The confidence is set at a fixed value and from that value the confidence interval is estimated. It still uses the sample proportion instead of the confidence interval to estimate the true proportion.

(c) We are 95 % confident the proportion of adults in the country during the period of economic uncertainty who believed wages paid to workers in industry were too low was between 0.59 and 0.67. Is the interpretation reasonable?

A.The interpretation is reasonable.

It uses the right sample data and interpret correctly the meaning of the confidence interval.

(d) In 95 % of samples of adults in the country during the period of economic uncertainty, the proportion who believed wages paid to workers in industry were too low is between 0.59 and 0.67. Is the interpretation reasonable?

C.The interpretation is flawed. The interpretation suggests that this interval sets the standard for all the other intervals, which is not true.

This confidence interval is an estimation about the parameter of the population. It doesn't give information to estimate the sampling distribution, as it only has information of one specific sample.

6 0

3 years ago

Charles has $87 in his checking account. He spent $14 and $17, then deposited $33. If he wants to buy a television that cost $18

tester [92]

Answer:

He need $99 more

Step-by-step explanation:

87-14-17=56+33=89

188-89=99

5 0

3 years ago

Read 2 more answers

How many solutions does the following have? 1x-5y=15 -1+5y=-15