A simple random sample of size n is drawn from a population that is normally distributed. The sample​ mean, x​, is found to be 115​, and the sample standard​ deviation, s, is found to be 10.    ​(a) Construct a 98​% confidence interval about μ if the sample​ size, n, is 18. Lower​ bound:___ Upper​ bound:____ ​(Use ascending order. Round to one decimal place as​ needed.)   ​(b) Construct a 98​% confidence interval about μ if the sample​ size, n, is 29.  lower bound ___ upper bound___ ​(Use ascending order. Round to one decimal place as​ needed.) ​ (c) Construct a 99​% confidence interval about μ if the sample​ size, n, is

MATLAB: An Introduction with Applications
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ISBN:9781119256830
Author:Amos Gilat
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Chapter1: Starting With Matlab
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A simple random sample of size n is drawn from a population that is normally distributed. The sample​ mean, x​, is found to be 115​, and the sample standard​ deviation, s, is found to be 10. 
 
​(a) Construct a 98​% confidence interval about μ if the sample​ size, n, is
18.
Lower​ bound:___
Upper​ bound:____ ​(Use ascending order. Round to one decimal place as​ needed.)
 
​(b) Construct a 98​% confidence interval about μ if the sample​ size, n, is
29. 
lower bound ___
upper bound___ ​(Use ascending order. Round to one decimal place as​ needed.)
(c) Construct a 99​% confidence interval about μ if the sample​ size, n, is
18.
Lower bound ___
Upper bound___  ​(Use ascending order. Round to one decimal place as​ needed.)
(d) Could we have computed the confidence intervals in parts​ (a)-(c) if the population had not been normally​ distributed?
Table of t-Distribution Areas
318.309
22.327
10.215
7.173
1
1.000
1.376
1.061
0.978
1.963
1.386
1.250
1.190
1.156
3.078
1.886
1.638
1.533
1.476
6.314
12.706
4.303
3.182
15.894
31.821
63.657
127.321
636.619
6.965
4.541
3.747
3.365
0.816
2.920
2.353
2.132
2.015
4.849
3.482
2.999
2.757
9.925
5.841
4.604
4.032
14.089
7.453
5.598
4.773
31.599
12.924
3
0.765
4
0.741
0.941
2.776
8.610
6.869
5
0.727
0.920
2.571
5.893
0.718
0.711
2.612
2.517
0.906
1.134
1.440 1.943
2.447
2.365
2.306
2.262
3.143
3.707
4.317
5.208
4.785
5.959
5.408
5.041
4.781
0.896
2.998
1.415 1.895
1.108 1.397 1.860
1.383
1.372
1.119
2.449
2.398
2.359
3.499
3.355
3.250
3.169
4.029
3.833
3.690
4.501
4.297
8
0.706
0.703
0.700
0.889
0.883
0.879
2.896
2.821
9
1.100
1.833
10
1.093
1.812
2.228
2.764
3.581
4.144
4.587
2.201
2.179
2.160
2.145
3.497
3.428
3.372
4.025
3.930
3.852
3.787
3.733
0.876
0.873
11
1.088
0.697
0.695
1.363
1.356
1.350
1.345
1.341
1.796
2.328
2.303
2.718
3.106
3.055
3.012
2.977
2.947
4.437
4.318
4.221
1.782
2.681
2.650
12
1.083
1.079
13
2.282
2.264
2.249
0.694
0.870
1.771
14
0.692
1.076
1.761
2.624
3.326
3.286
4.140
4.073
0.868
15
0.691
0.866
1.074
1.753
2.131
2.602
2.120
2.110
2.101
2.235
2.224
2.583
2.567
2.552
2.539
2.528
0.690
1.071
1.069
1.337
2.921
2.898
3.252
4.015
3.965
16
0.865
0.863
0.862
1.746
3.686
3.646
3.610
3.579
3.552
17
0.689
0.688
0.688
0.687
1.333
1.740
3.222
3.197
3.174
3.153
3.922
3.883
3.850
2.878
2.861
18
1.067
1.330
1.734
2.214
1.066
1.064
19
0.861
1.328
1.729
2.093
2.205
20
0.860
1.325
1.725
2.086
2.197
2.845
1.063
1.061
1.060
1.323 1.721
1.321
2.518
2.508
2.500
2.492
2.485
21
0.686
0.859
2.080
2.189
2.831
3.135
3.119
3.104
3.091
3.078
3.527
3.819
0.858
0.858
2.183
2.177
2.172
22
2.074
3.792
0.686
0.685
0.685
1.717
2.819
3.505
3.485
1.714
23
24
1.319
1.318
2.069
2.064
2.060
2.807
3.768
0.857
0.856
1.059
1.711
2.797
3.467
3.745
25
0.684
1.058
1.316
1.708
2.167
2.787
3.450
3.725
2.162
2158.
3.067
3.435
3 421
26
0.856
0 85.
1.058
1.315 1.706
1 314.
1 703.
2.056
2.479
2 473.
2.779
2 771.
0.684
3.707
27
0 684
1 057
2052
3.057
3.690
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Transcribed Image Text:Table of t-Distribution Areas 318.309 22.327 10.215 7.173 1 1.000 1.376 1.061 0.978 1.963 1.386 1.250 1.190 1.156 3.078 1.886 1.638 1.533 1.476 6.314 12.706 4.303 3.182 15.894 31.821 63.657 127.321 636.619 6.965 4.541 3.747 3.365 0.816 2.920 2.353 2.132 2.015 4.849 3.482 2.999 2.757 9.925 5.841 4.604 4.032 14.089 7.453 5.598 4.773 31.599 12.924 3 0.765 4 0.741 0.941 2.776 8.610 6.869 5 0.727 0.920 2.571 5.893 0.718 0.711 2.612 2.517 0.906 1.134 1.440 1.943 2.447 2.365 2.306 2.262 3.143 3.707 4.317 5.208 4.785 5.959 5.408 5.041 4.781 0.896 2.998 1.415 1.895 1.108 1.397 1.860 1.383 1.372 1.119 2.449 2.398 2.359 3.499 3.355 3.250 3.169 4.029 3.833 3.690 4.501 4.297 8 0.706 0.703 0.700 0.889 0.883 0.879 2.896 2.821 9 1.100 1.833 10 1.093 1.812 2.228 2.764 3.581 4.144 4.587 2.201 2.179 2.160 2.145 3.497 3.428 3.372 4.025 3.930 3.852 3.787 3.733 0.876 0.873 11 1.088 0.697 0.695 1.363 1.356 1.350 1.345 1.341 1.796 2.328 2.303 2.718 3.106 3.055 3.012 2.977 2.947 4.437 4.318 4.221 1.782 2.681 2.650 12 1.083 1.079 13 2.282 2.264 2.249 0.694 0.870 1.771 14 0.692 1.076 1.761 2.624 3.326 3.286 4.140 4.073 0.868 15 0.691 0.866 1.074 1.753 2.131 2.602 2.120 2.110 2.101 2.235 2.224 2.583 2.567 2.552 2.539 2.528 0.690 1.071 1.069 1.337 2.921 2.898 3.252 4.015 3.965 16 0.865 0.863 0.862 1.746 3.686 3.646 3.610 3.579 3.552 17 0.689 0.688 0.688 0.687 1.333 1.740 3.222 3.197 3.174 3.153 3.922 3.883 3.850 2.878 2.861 18 1.067 1.330 1.734 2.214 1.066 1.064 19 0.861 1.328 1.729 2.093 2.205 20 0.860 1.325 1.725 2.086 2.197 2.845 1.063 1.061 1.060 1.323 1.721 1.321 2.518 2.508 2.500 2.492 2.485 21 0.686 0.859 2.080 2.189 2.831 3.135 3.119 3.104 3.091 3.078 3.527 3.819 0.858 0.858 2.183 2.177 2.172 22 2.074 3.792 0.686 0.685 0.685 1.717 2.819 3.505 3.485 1.714 23 24 1.319 1.318 2.069 2.064 2.060 2.807 3.768 0.857 0.856 1.059 1.711 2.797 3.467 3.745 25 0.684 1.058 1.316 1.708 2.167 2.787 3.450 3.725 2.162 2158. 3.067 3.435 3 421 26 0.856 0 85. 1.058 1.315 1.706 1 314. 1 703. 2.056 2.479 2 473. 2.779 2 771. 0.684 3.707 27 0 684 1 057 2052 3.057 3.690 Print Done parts remaining Clear All
i Table of t-Distribution Areas
2.056
1.315
1.314
3.067
3.057
3.047
3.038
26
0.856
2.779
0.684
0.684
1.058
1.057
1.056
1.055
1.055
1.706
2.162
2.479
3.435
3.707
0.855
0.855
0.854
27
1.703
2.052
2.158
2.154
2.150
2.147
2.473
2.771
3.421
3.408
3.396
3.385
3.690
28
29
0.683
0.683
0.683
1.313
1.311
1.701
1.699
2.048
2.045
2.042
2.467
2.462
2.457
2.763
2.756
3.674
3.659
30
0.854
1.310
1.697
2.750
3.030
3.646
1.054
1.054
1.053
1.052
1.052
3.375
3.365
3.356
3.348
3.340
0.682
1.309
1.696
2.744
2.738
2.733
2.728
2.724
31
32
0.853
2.040
2.144
2.141
2.138
2.136
2.133
2.453
2.449
3.022
3.633
3.622
3.611
1.694
1.692
1.691
1.690
3.015
3.008
3.002
2.996
0.853
1.309
2.037
0.682
0.682
33
34
0.853
0.852
1.308
1.307
2.035
2.032
2.030
2.445
2.441
2.438
0.682
3.601
35
0.682
0.852
1.306
3.591
2.028
2.026
36
0.852
1.052 1.306
1.305
1.304
2.131
3.333
3.326
3.319
3.313
3.307
3.582
3.574
3.566
0.681
1.688
2.434
2.431
2.719
2.990
2.985
37
38
39
2.715
2.712
2.708
0.681
0.851
0.851
0.851
1.051
1.051
1.050
1.687
2.129
1.686
1.685
1.684
2.127
2.125
2.123
0.681
2.024
2.429
2.426
2.980
2.976
2.971
2.023
3.558
3.551
0.681
1.304
40
0.681
0.851
1.050
1.303
2.021
2.423
2.704
2.937
2.915
3.496
3.460
3.435
3.416
0.679
0.679
0.849
1.047
1.676
2.009
2.000
1.994
2.678
50
60
1.299
1.296
2.109
2.099
2.093
2.088
2.084
3.261
3.232
3.211
2.403
2.390
1.045
1.044
0.848
1.671
2.660
70
0.678
0.847
1.294
1.667
2.381
2.648
2.639
2.632
2.899
1.043
1.042
2.887
80
90
0.678
0.677
1.664
1.662
3.195
3.183
0.846
1.292
1.291
1.990
2.374
2.368
0.846
1.987
2.878
3.402
1.042
1.037
1.290
1.282
1.282
2.626
2.581
2.576
100
0.677
0.845
0.842
0.842
1.660
1.984
1.962
1.960
2.081
2.056
2.054
2.364
2.871
2.813
2.807
3.174
3.390
1000
0.675
1.646
2.330
3.098
3.300
0.674
1.036
1.645
2.326
3.090
3.291
df
0.25
0.20
0.15
0.10
0.05
0.025
0.02
0.01
0.005
0.0025
0.001
0.0005
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Transcribed Image Text:i Table of t-Distribution Areas 2.056 1.315 1.314 3.067 3.057 3.047 3.038 26 0.856 2.779 0.684 0.684 1.058 1.057 1.056 1.055 1.055 1.706 2.162 2.479 3.435 3.707 0.855 0.855 0.854 27 1.703 2.052 2.158 2.154 2.150 2.147 2.473 2.771 3.421 3.408 3.396 3.385 3.690 28 29 0.683 0.683 0.683 1.313 1.311 1.701 1.699 2.048 2.045 2.042 2.467 2.462 2.457 2.763 2.756 3.674 3.659 30 0.854 1.310 1.697 2.750 3.030 3.646 1.054 1.054 1.053 1.052 1.052 3.375 3.365 3.356 3.348 3.340 0.682 1.309 1.696 2.744 2.738 2.733 2.728 2.724 31 32 0.853 2.040 2.144 2.141 2.138 2.136 2.133 2.453 2.449 3.022 3.633 3.622 3.611 1.694 1.692 1.691 1.690 3.015 3.008 3.002 2.996 0.853 1.309 2.037 0.682 0.682 33 34 0.853 0.852 1.308 1.307 2.035 2.032 2.030 2.445 2.441 2.438 0.682 3.601 35 0.682 0.852 1.306 3.591 2.028 2.026 36 0.852 1.052 1.306 1.305 1.304 2.131 3.333 3.326 3.319 3.313 3.307 3.582 3.574 3.566 0.681 1.688 2.434 2.431 2.719 2.990 2.985 37 38 39 2.715 2.712 2.708 0.681 0.851 0.851 0.851 1.051 1.051 1.050 1.687 2.129 1.686 1.685 1.684 2.127 2.125 2.123 0.681 2.024 2.429 2.426 2.980 2.976 2.971 2.023 3.558 3.551 0.681 1.304 40 0.681 0.851 1.050 1.303 2.021 2.423 2.704 2.937 2.915 3.496 3.460 3.435 3.416 0.679 0.679 0.849 1.047 1.676 2.009 2.000 1.994 2.678 50 60 1.299 1.296 2.109 2.099 2.093 2.088 2.084 3.261 3.232 3.211 2.403 2.390 1.045 1.044 0.848 1.671 2.660 70 0.678 0.847 1.294 1.667 2.381 2.648 2.639 2.632 2.899 1.043 1.042 2.887 80 90 0.678 0.677 1.664 1.662 3.195 3.183 0.846 1.292 1.291 1.990 2.374 2.368 0.846 1.987 2.878 3.402 1.042 1.037 1.290 1.282 1.282 2.626 2.581 2.576 100 0.677 0.845 0.842 0.842 1.660 1.984 1.962 1.960 2.081 2.056 2.054 2.364 2.871 2.813 2.807 3.174 3.390 1000 0.675 1.646 2.330 3.098 3.300 0.674 1.036 1.645 2.326 3.090 3.291 df 0.25 0.20 0.15 0.10 0.05 0.025 0.02 0.01 0.005 0.0025 0.001 0.0005 Area in Right Tail Print Done parts remaining Clear All
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