Question

hello i need help solving this problems please

c. In a group of 230 tests, how many students score within one standard deviation of the men? 19. The number of roils of a given length is normally distributed with a mean length of 5.00 in and a standard deviation of 0.03 in a. Find the number of nails in a bag of 120 thet are less than 494 in long b. Find the number of nails in a bag of 120 that ere between 4.97 and 5.03 in long c. Find the number of nails in a bag of 120 that are over 5.03 in long. 20. The actual weights of bags of pet food are normally distributed. The mean of the weights is 500 lb, with a standard deviation of 0.2 lb. Use the graph for e-c . About what percent of bags of pet food weigh less Wha than 49.8b b. In a group of 250 bags, how many would you expect to weigh more than 50.4 lb? Wond c. In a group of 50 bags, how many would you expect to be within 15 standard deviations of the mean) 21. In the accompanying diagram, the shaded area represents approximately 95% of the scores on a standardized test. If these scores ranged from 78 to 92, a) What is the mean? b) What is the standard deviation 22. A machine is used to put bolts into boxes. It does to such that the actual number of bolts in a box is normally distributed with a mean of 106 and a standard deviation of 2. a) Drow and label the Normal curve from the information b) What percentage of boxes contain more than 104 bolts? What percentage of bones contain more than 110 bolts? 49 What percentage of boxes contain less than 108 balts c) What percentage of bones contain less than 100 bolts f) What percentage of boxes contain between 10 and 112 bolts? g) What percentage of boxes contain between 100 end 106 bolt 23. The heights of the people if the planet Ixx are normally distributed with a mean of 40 inches and standard deviation of 5 inches. They are a vertically diverse people] a) Draw and label the Normal curve from the information ) 97.5% of Dexions are over - inches tal 97.5% <) 16% of Toxiandere over inches alb 50% of Lovers are under inches tall .) 97.5% of Ixxions are under Inches toll? f) the most everage" 68% of Davies are between inches tall? 9) 84% of Lexions are over_inches toll? 24. On a standardized test, Phyllis scored 4. exactly one standard deviation above the neon If the standard deviation for the test is 6, what is the mean score for the test? 25. The heights of a group of girls are normally distributed with a mean of 66 inches. If 95% of the heights of these girls are between 63 and 69 inches, what is the standard deviation for this group

Answer 1

x QO 19. Let x be the number of nails of a given length. Then ~ Normal cu: 5,0:0:03) a) We need to find the number of nails is a bog of that core less than 4.94 long. P(x24.94). PC*< 4.94 ) plz<-2) From standard normal table Plz<-2)= 0.0228 P(24-^) .. Number of nails is the bag that are less than 44.94 in long 1 0.0228XO -2.736 3 : 3 Required Number of nails 16 We need to find the number of nails in a of 12o that are between 4.970 and 5.03 in p(4.97 <x<5.03). P (4.9 bag long. X-M 5.03 - 5 4.97-5 0.03 < 3) 0.03 p(-1<z«!) EP-<z) From standard normal table, P(-1<z21) : 0.6806 ... Number of nails is the bag that are between 4.91 and 5.03 in long 0.6826xIDO 81.910 82 Requined number of nails : 82 (c) We need to find the number of nails in a bog 120 that are 5.03 in. long P( x >5:03) p(*4> Oven 5.03 - 5 :) P(Z >1). From standard normal table, prz> 1 )= 0.1587 plz>') N ". Number of nails in the bag long that are over 5.03 in. 0.1587 x 20 19.044 19 Required number of nails : 19 Scanned with CamScanner

I have answered the first question as per Chegg answering guidelines. If you need help with other questions also, you can post them as separate question and the experts will always be available to help you.

Please upvote my answer if you find it helpful. Thanking you.