I'm Very confused

The data in Mac nery.xlsx shows the data for a manufacturer who is considering replacing machinery records the age oi each machine (in months) and the amount spent on repairing each machine (3). Download these data and perform a linear regression in Excel to determine whether age oi machinery useiul for predicting repair costs. Use the output from your regression and the residual diagnostic plots irom this analysis which are given below to answer the questions which follow. Histogram of residuals Residual plot '0 o . oo o o o F' 0 o o o o F 2 a 0 o 0 (1:; = o q oa ' o 3 E o o o a w o o o to c g .n g '7 3 o D o c, ll l ".' o I I I i -20 -10 0 10 Reslduals 63101214t6 Age Answer the iollowing questions by choosing the most correct option or typing the answer: it (1 mark) Create a scatterplot oi repair cost against age. The relationship shown in the scatterplot is positive = v 2. (1 mark) The histogram of residuals is approximately normally distributedot too skewed s v a. (1 mark) The residual plot shows a random scatter or points tor the whole range at ages Irue . v A. (1 mark) The piece at machinery that is the oldest also has the most repair costs true a v 5. (2 marks) The piece oi machinery with the largest residual had an age of 10.59 and had a repair cost of 40.044 dollars. Calculate the value oi the residual. Type your answer with 3dp. 2.257 x a. (2 marks) The slope of the regression line is equal to (type your answer with mm: 0.201 x 7. (1 mark) The p-value for testing the slope of the regression line is less than 0.05. false : x 8. (2 marks) The most appropriate conclusion to the question: Is age a uselul predictor of the repair cost of machinery? There is a significant positive linear relationship between age and repair cost - v St (1 mark) The correlation is (type your answer with SdD): 0.954 X 10, (1 mark) Can we predict age when repair cost is 26? Yes a x ii. (2 marks) Use the regression equation to predict the cost repairing a machine when the machine age is 11. Type your answer with ado. 3.392 x 12' [3 marks) We are 95% confident that for each year older the repair cost increases 3 0/ between X and & dollars, Type your answer with 341;). A B 1 age cost 2 9.31712 20.05091 3 6.056959 18.06111 4 9.538562 22.16538 5 12.21019 23.65871 6 16.67021 27.04914 7 6.137387 13.93883 8 13.84271 42.67534 9 11.31731 19.66971 10 13.78911 23.47308 11 9.493321 30.58806 12 11.76465 25.25948 13 6.391326 16.60581 14 13.9049 33.62949 15 5.142581 18.32393 16 8.083554 18.54039 17 10.82683 35.2053 18 11.99113 40.87204 19 6.771607 10.79322 20 9.04684 13.81994 21 15.78706 10.11496 22 11.53953 23.11854 23 11.28825 24.93168 24 12.47431 29.51805 25 10.88709 38.7956 26 18.21538 33.59353 27 10.52083 12.85597 28 10.32115 37.38197 29 5.402142 19.5843 30 12.91477 26.35711 31 17.59213 32.97113 32 19.24108 53.07703 33 5.278231 22.73553 34 14.11757 39.67598 35 15.66498 25.22112 36 8.555174 20.51558 37 6.861471 20.94805 38 13.4211 35.34014 39 10.64637 16.146 40 7.430325 16.94247 41 17.74594 46.30973 42 9.219474 13.93715 43 11.21811 19.3906 44 11.57844 14.58933 45 10.59211 15.23585 46 13.02712 42.25757 47 16.90933 34.83773 10.59032 40.04397 49 12.81861 12.06654 50 9.039821 22.14794 51 15.82009 38.38353