Structurally deficient highway bridges. Data onstructurally deficient highway bridges is compiled by the FederalHighway Administration (FHWA) and reported in the National BridgeInventory (NBI). For each state, the NBI lists the number ofstructurally deficient bridges and the total area (thousands ofsquare feet) of the deficient bridges. The data for the 50 states(plus the District of Columbia and Puerto Rico). For futureplanning and budgeting, the FHWA wants to estimate the total areaof structurally deficient bridges in a state based on the number ofdeficient bridges

NumberSD	SDArea
1899	432.71
155	60.92
181	110.57
997	347.35
3140	5177.97
580	316.92
358	387.78
20	9.05
24	59.34
302	412.92
1028	344.86
142	39.8
349	135.43
2501	1192.43
2030	688.19
5153	1069.71
2991	527.47
1362	458.37
1780	1453.26
349	131.13
388	236.18
585	521.83
1584	804.15
1156	325.9
3002	692.75
4433	1187.42
473	90.94
2382	335.75
47	20.08
383	127.66
750	752.43
404	196.67
2128	1427.73
2272	1034.61
743	101.42
2862	965.16
5793	1423.25
514	393.96
5802	2404.61
164	237.96
1260	626.38
1216	209.33
1325	481.31
2186	1031.45
233	102.56
500	153.8
1208	483.68
400	502.03
1058	331.59
1302	399.8
389	143.46
241	195.43

a) Deplaned on scatterplot, can you use linear regression topredict SDArea based onNumberSD? Explain.

b) Develop a simple linear regression equation to predict SDAreabased on NumberSD.

c) Is the model you found in (a) a good fit? Why or why not?

d) Predict the SDArea when the NumberSD is 1260 bridges. Findthe corresponding residuals.

e) Build a 90% CI, confidence interval, for coefficient ofNumberSD ( b₁).

f) Repeat (e) with a 95% CI. What is the difference between youranswer in (e) and (f)?