could I please get help with a problem I am having trying to do a linear regression?

General
1

"#plot the regression line
plot(data$speed,data$power, col = "blue", xlab = "speed", ylab = "power")
abline(speedpower1, lwd=5, col="red")

#prediction
say <- data.frame(data$speed = 8.7)
predict(speedpower1, say)

Why would this error occur? Thanks!

"say <- data.frame(data$speed = 8.7)
Error: unexpected '=' in "say <- data.frame(data$speed ="

2

When R reads data$speed, it 'thinks' you want the contents of that vector, but I'm guessing you just want to create a column with that name -- is that right?

3

yes, i figured it out. Thanks for the help

4

h say <- data.frame(speed=8.7)

predict(speedpower1, say)
Error in model.frame.default(Terms, newdata, na.action = na.action, xlev = object$xlevels) :
object is not a matrixmm. then this.

any help. thanks

5

What is speedpower1? Where did it come from?

6

it is a "list of 12" values.

#plot the regression line
plot(data$speed,data$power, col = "blue", xlab = "speed", ylab = "power")
abline(speedpower1, lwd=5, col="red")

#prediction
say <- data.frame(speed = 8.7)
predict(speedpower1, say)

7

Could you post the output to str(speedpower1)?

8

str(speedpower1)
List of 12
coefficients : Named num [1:2] 8.92 2.45 ..- attr(*, "names")= chr [1:2] "(Intercept)" "power" residuals : Named num [1:2544] -6.016 -1.316 2.153 0.378 0.333 ...
..- attr(, "names")= chr [1:2544] "1" "2" "3" "4" ...
effects : Named num [1:2544] -891.842 373.019 2.287 0.499 0.454 ... ..- attr(*, "names")= chr [1:2544] "(Intercept)" "power" "" "" ... rank : int 2
fitted.values: Named num [1:2544] 8.92 8.92 12.35 16.02 16.27 ... ..- attr(*, "names")= chr [1:2544] "1" "2" "3" "4" ... assign : int [1:2] 0 1
qr :List of 5 .. qr : num [1:2544, 1:2] -50.4381 0.0198 0.0198 0.0198 0.0198 ...
.. ..- attr(, "dimnames")=List of 2
.. .. .. : chr [1:2544] "1" "2" "3" "4" ... .. .. .. : chr [1:2] "(Intercept)" "power"
.. ..- attr(, "assign")= int [1:2] 0 1
.. qraux: num [1:2] 1.02 1.02 .. pivot: int [1:2] 1 2
.. tol : num 1e-07 .. rank : int 2
..- attr(, "class")= chr "qr"
df.residual : int 2542 xlevels : Named list()
call : language lm(formula = speed ~ power, data = data) terms :Classes 'terms', 'formula' language speed ~ power
.. ..- attr(, "variables")= language list(speed, power)
.. ..- attr(, "factors")= int [1:2, 1] 0 1
.. .. ..- attr(, "dimnames")=List of 2
.. .. .. .. : chr [1:2] "speed" "power" .. .. .. .. : chr "power"
.. ..- attr(, "term.labels")= chr "power"
.. ..- attr(, "order")= int 1
.. ..- attr(, "intercept")= int 1
.. ..- attr(, "response")= int 1
.. ..- attr(, ".Environment")=<environment: R_GlobalEnv>
.. ..- attr(, "predvars")= language list(speed, power)
.. ..- attr(, "dataClasses")= Named chr [1:2] "numeric" "numeric"
.. .. ..- attr(, "names")= chr [1:2] "speed" "power"
model :'data.frame': 2544 obs. of 2 variables: .. speed: num [1:2544] 2.9 7.6 14.5 16.4 16.6 1.6 10.1 23.8 42.4 18.9 ...
.. power: num [1:2544] 0 0 1.4 2.9 3 0 0.2 6.2 7.4 3.5 ... ..- attr(*, "terms")=Classes 'terms', 'formula' language speed ~ power .. .. ..- attr(*, "variables")= language list(speed, power) .. .. ..- attr(*, "factors")= int [1:2, 1] 0 1 .. .. .. ..- attr(*, "dimnames")=List of 2 .. .. .. .. .. : chr [1:2] "speed" "power"
.. .. .. .. ..$ : chr "power"
.. .. ..- attr(, "term.labels")= chr "power"
.. .. ..- attr(, "order")= int 1
.. .. ..- attr(, "intercept")= int 1
.. .. ..- attr(, "response")= int 1
.. .. ..- attr(, ".Environment")=<environment: R_GlobalEnv>
.. .. ..- attr(, "predvars")= language list(speed, power)
.. .. ..- attr(, "dataClasses")= Named chr [1:2] "numeric" "numeric"
.. .. .. ..- attr(*, "names")= chr [1:2] "speed" "power"

  • attr(*, "class")= chr "lm"

Thanks for the help!!!

9

Sure: When you post here, you should do it this way:

```
<--- paste here, including the ```s
```

Could you do that?

10

sorry. i am a beginner

11

No worries, but could you re-post

the way I suggested?

12

I am sorry. I dont understand. Do you want me to copy and paste code into another area? is the what the arrow means?

13

You could click the 'Edit' icon on your post, and type ``` before and after the code you already posted there -- could you try that?

14

I am still confused, but I did try to edit. Is there a faq i could read to understand better?

15

Could you run summary(speedpower1) and paste the output here between a pair of triple backticks, like this?

```
<---- paste output here
```
16 
Call:
lm(formula = speed ~ power, data = data)

Residuals:
    Min      1Q  Median      3Q     Max 
-25.334  -3.953  -0.716   2.202  49.884 

Coefficients:
            Estimate Std. Error t value Pr(>|t|)    
(Intercept)  8.91611    0.21134   42.19   <2e-16 ***
power        2.45036    0.04515   54.27   <2e-16 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Residual standard error: 6.874 on 2542 degrees of freedom
Multiple R-squared:  0.5367,	Adjusted R-squared:  0.5365 
F-statistic:  2945 on 1 and 2542 DF,  p-value: < 2.2e-16

thanks for the help. I am trying to do a regression with predict function

1 Like
17

This shows that you're predicting speed data from power data, so you need new power data to make new predictions.

This shows you're trying to supply speed data to the predict() function, but you need to supply power data. Could you try that?

18

yes, thank you for the help

1 Like
19

unexpected error in ggplot with time series

autoplot(ts(train$Prices.BE,frequency = 24, ylab = "Price BE")
autoplot(ts(train$Prices.BE,frequency = 24, ylab = "Price BE", ylim = (c,200))
20

Hi @JamesVU2000: You should post a separate question since this is unrelated to your original question, and you should include 1) the data you're using, 2) the code and packages you're using, and 3) the error messages you're getting. The best way to do this is to follow this guide: FAQ: How to do a minimal reproducible example ( reprex ) for beginners.