1.Use the Q10 dataframe. Consider three standard multiple linear regression models predicting Sales from both predictors and no interaction (i. e., ignoring the time series nature of the data): one with a linear trend, one with a quadratic trend, and one with a cubic trend. In the model with lowest of the three AICs, ( Just Write the code for RStudio)

2.Reconsider your model and data from Q10. Now impose an autoregressive model on the residuals. In other words, consider three additional models predicting Sales from Quarter and Month (no interactions but with whichever kind of trend was appropriate in Q10) with an autoregressive model for the residuals of lag 1, lag 2, and lag 3.Note: Quarter is a categorical variable, independent of the trend, so do not use poly() on it.
In the model with lowest of the four AICs, report the STANDARD ERROR of the difference in average sales between First Quarter and Third Quarter. Note: this requires installation and loading of the library nlme. So you'll have to do install. packages('nlme') then library(nlme) (Just Write the code for RStudio)

dataframe 10 is in the regclass of RStudio 's packages

2 & 7

step-by-step explanation:

he climbs 300 ft/hr at a constant rate. the peak is at 1,500 ft.

when going up, he reaches 600 ft in 2 hours. remember, that he is going in a constant rate. divide 600 with 300:

600/300 = 2

assuming that he takes the same route back (meaning that it's a 1500 ft route back, you can solve.

note also that you are solving when he gets back to 600 ft after he reaches the peak.

first, find the amount of hours it takes to get up the peak. divide the total amount (1500), with the ft/her (300) to get the amount of hours (x):

1500/300 = x

x = 5

it takes jamie 5 hours to get up. now, he is returning down, and reaches 600 (his current destination). remember that he climbs at a constant 300 ft/hr. divide 600 with 300:

600/300 = x

x = 2

now add the two numbers together.

x = 5 + 2 = 7

jamie takes 7 hours to go up the mountain and reach his current position when descending.

(total amount/constant rate) = (time).

remember that it is a constant rate, so in total, when he gets back down the mountain, it will take the same amount of time as when he goes up. the total amount for the round trip is: 5 + 5 = 10.

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r = 78539458390583095803458309458039485093485 or just 3

step-by-step explanation:

c.

step-by-step explanation: