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3 years ago

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In a sample of 56 bags of fertilizer, the average weight was found to be 17.2lb with a standard deviation of 0.7. Give a point e

stimate for the population standard deviation of the weight of the bags of fertilizer.

1 answer:

Natali5045456 [20]3 years ago

5 0

Answer:

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A train leaves at 1314 and arrives at 1508. It travelled at an average speed of 105 km/h.

Paraphin [41]

Answer: The train traveled 199.5 km

Step-by-step explanation:

We know the relationship:

Distance = Time*Speed

We know that the speed of the train was 105km/h

And we know that it leaves at 13:14, and arrives at 15:08.

Then the total amount of time that the train was traveling is:

T = (15 hours and 8 mins) - (13 hours and 14 mins)

= (15 - 13) hours and (8 - 14) mins

= 2 hours and (-6) mins.

We know that one hour has 60 minutes, then this is equal to:

T = 1 hour and 54 minutes.

But because the speed is kilometers per hour, we need to rewrite the 54 minutes in hours.

This can be done as follows:

1 hour = 60 minutes.

Then: 54 minutes = (54/60) hours = 0.9 hours.

Then:

1 hour and 54 minutes = 1.9 hours.

Now we know the speed and the time, then the distance can be calculated as:

Distance = speed*time = 105km/h*(1.9 h) = 199.5 km

The train traveled 199.5 km

3 0

3 years ago

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Which of these is a simplified form of the equation 7y + 8 = 9 + 3y + 2y?

Lera25 [3.4K]

Answer:

7y +8 is the answer for the question

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3 years ago

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This is question What value does the 6 represent in the number 976.14?

UkoKoshka [18]

Answer:

Ones place

Step-by-step explanation:

9 in 976.14 is the hundreds place.

7 is the tens place.

6 is the ones place.

1 is the tenths place.

4 is the hundredths place.

8 0

3 years ago

Read 2 more answers

What are two different ways of factoring –3x – 9? Select all that apply. A. –3(x + 3) B. 3(x + 3) C. 3(–x – 3) D. –3(x – 3)

Shalnov [3]

A. and C. Are both correct

3 0

3 years ago

An instructor in a college class recently gave an exam that was worth a total of 100 points. The instructor inadvertently made t

solniwko [45]

Answer:

B) Method 2 will increase the standard deviation of the students' scores.

Step-by-step explanation:

Given that an instructor in a college class recently gave an exam that was worth a total of 100 points.

The average score for his students was 43 and the standard deviation of the scores was 5 points.

And now he is considering two different strategies for rescaling the exam results of which:

Method 1 = Add 17 points to everyone's score.

Method 2 = Multiply everyone's score by 1.7 .

And we have to check what will be the impact of these methods on the standard deviation of the students' scores.

For this let us consider a simple example to understand this:

Firstly, Formula for calculating Standard Deviation = $\sqrt{\frac{\sum (X-Xbar)^{2}}{n-1}}$

Suppose,

X X - Xbar $(X - Xbar)^{2}$

3 3 - 6 = -3 -3 * -3 = 9

5 5 - 6 = -1 -1 * -1 = 1

10 10 - 6 = 4 4 * 4 = 16

<em>Mean of above data, Xbar</em> = $\frac{3+ 5+10}{3}$ = 6

<em>Standard Deviation of data </em>= $\sqrt{\frac{26}{3-1} }$ = 3.6055

Now let us suppose that we multiply each value of above data with 2 so the new data will be:

X X - Xbar $(X - Xbar)^{2}$

3*2 = 6 6 - 12 = -6 -6 * -6 = 36

5*2 = 10 10 - 12 = -2 -2 * -2 = 4

10*2 =20 20 - 12 = 8 8 * 8 = 64

<em>Mean of new data, Xbar </em>= $\frac{6+ 10+20}{3}$ = 12

<em>Standard Deviation of new data</em> = $\sqrt{\frac{104}{3-1} }$ = 7.2111

<em>Hence, we see that when we multiply any value to the data the standard deviation will increase and in other words it will multiplied by that value which value we multiplied with each data value i.e. when we multiply each data value with 2 the standard deviation also get multiplied by as </em>

3.6055 * 2 = 7.2111

Therefore option B is correct that Method 2 will increase the standard deviation of the students' scores.

<em>And on the other hand Similarly by adding any constant to the data the Standard Deviation will remain same. Therefore Method 1 will have no impact on standard deviation of the students' scores.</em>

8 0

3 years ago