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EastWind [94]
2 years ago
6

For a set of data: x = (0,1,2,3,4,5,6) and y=(36, 28, 25, 24, 23, 21, 19), is it wise to use a linear regression to extrapolate

data for x = 50? Solution: Since the coefficient of determination is 0.8582, the linear model is a reasonably good fit for the data, so extrapolation for any x-value is acceptable. What is wrong with this solution?
Mathematics
1 answer:
melisa1 [442]2 years ago
4 0

Answer:

The problem with this solution is that a regression model is not recommended to extrapolate because we do not know if the linear relation that we calculated for a specific range of x values still holds outside this range.

Step-by-step explanation:

We have a linear regression model, with a range of the independent variable "x" that goes from 0 to 6.

The regression model finds a good fit (r=0.8582).

As it has a good fit, it is proposed to use this model to extrapolate and calculate the value of y for x=50.

It is not recommended to extrapolate a regression model unless we are really sure that the model is still valid within the range within we are extrapolating.

This means that if we have no proof that y has a linear relation in a range of x that includes x, the extrapolation has no validity and can lead to serious errors.

A linear regression model is only suitable for interpolation or extrapolating within the range we are sure that the relation between y and x is linear within a certain acceptable error.

You might be interested in
A phone manufacturer wants to compete in the touch screen phone market. Management understands that the leading product has a le
frutty [35]

Answer:

a) Null hypothesis:\mu_{1} - \mu_{2} \leq 120

Alternative hypothesis:\mu_{1} - \mu_{2}>120

b) Calculate the statistic

We can replace in formula (1) the info given like this:

t=\frac{(485-340)-120}{\sqrt{\frac{55^2}{100}+\frac{30^2}{120}}}}=4.0689  

c) Critical value

The first step is calculate the degrees of freedom, on this case:

df=n_{1}+n_{2}-2=100+120-2=218

The significance level on this case is 0.05 or 5% so we need to find a quantile on the t distribution with 218 degrees of freedom that accumulates 0.95 of the area on the left and 0.05 of the area on the right tail and this value can be founded with the following excel code: "=T.INV(1-0.05,218)" and we got:

t_{crit}= 1.652

Conclusion

Since our calculated value is higher than the critical value we have enough evidence to reject the null hypothesis at 5% of significance and then we can conclude that the new product has a battery life more than two hours (120 minutes) longer than the leading product

Step-by-step explanation:

Data given and notation

\bar X_{1}= 8*60 +5 =485 represent the mean for the new sample

\bar X_{2}=5*60+40=340 represent the mean for the old sample

s_{1}=55 represent the sample standard deviation for the new sample

s_{2}=30 represent the sample standard deviation for the old sample

n_{1}=100 sample size selected for the new sample

n_{2}=120 sample size selected for the old sample

\alpha=0.05 represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

p_v represent the p value for the test (variable of interest)

a) State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the new product has a battery life more than two hours longer than the leading product., the system of hypothesis would be:

Null hypothesis:\mu_{1} - \mu_{2} \leq 120

Alternative hypothesis:\mu_{1} - \mu_{2}>120

If we analyze the size for the samples both are higher than 30 but we don't know the population deviations so for this case is better apply a t test to compare means, and the statistic is given by:

t=\frac{(\bar X_{1}-\bar X_{2})- \Delta}{\sqrt{\frac{s^2_{1}}{n_{1}}+\frac{s^2_{2}}{n_{2}}}} (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other".

b) Calculate the statistic

We can replace in formula (1) the info given like this:

t=\frac{(485-340)-120}{\sqrt{\frac{55^2}{100}+\frac{30^2}{120}}}}=4.0689  

c) Critical value

The first step is calculate the degrees of freedom, on this case:

df=n_{1}+n_{2}-2=100+120-2=218

The significance level on this case is 0.05 or 5% so we need to find a quantile on the t distribution with 218 degrees of freedom that accumulates 0.95 of the area on the left and 0.05 of the area on the right tail and this value can be founded with the following excel code: "=T.INV(1-0.05,218)" and we got:

t_{crit}= 1.652

Conclusion

Since our calculated value is higher than the critical value we have enough evidence to reject the null hypothesis at 5% of significance and then we can conclude that the new product has a battery life more than two hours (120 minutes) longer than the leading product

7 0
2 years ago
3,6,10,5, 16,3,6<br><br> Mean is 7<br> Median<br><br> what’s the median? and is the mean correct?
mamaluj [8]

Answer:

Mean:7 Median:6

Step-by-step explanation:

Okay so the Median is 6, and the mean is correct.

6 0
2 years ago
Read 2 more answers
in a two digit number the sum of the digits is 9 if the digits are reversed the number is increased by 9 find the number
leva [86]

Answer:

1474

Step-by-step explanation:


3 0
2 years ago
the performing arts department put in its spring show on Friday and Saturday nights. the price of a ticket was the same both nig
Galina-37 [17]
Let p= the price of a ticket
Let c= the cost to put on the show

Formula:
(profit) = (ticket price) * (number of people) - (cost to put on show)
We have two equations here:
500=120p-c
400=100p-c
Solve:
100=20p
⇒p=5
⇒400=100(5)-c
⇒400=500-c
⇒c=100

So the price of a ticket is $5, and the cost to put on the show is $100.
3 0
2 years ago
Please need help on this
zimovet [89]

Answer:

7047, people/km^2

Step-by-step explanation:

To find the answer, you would need to divide the numbers 8550405(people) and 1213.4(kilometers) <--- which where this came from.

Once you divide those numbers, you will directly get the number 7047 as your answer.

<h2>Please Mark me as brainly! Thank You!</h2>
4 0
3 years ago
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