For some reason I have a feeling 1a. is kind of a 'trick' question, where the answer is in the first paragraph. I have a feeling the answer is 65kg, but hey, I could be wrong. If someone could point me in the direction of how to figure this out, it would be greatly appreciated.
1. A lift in a building carriers 25 passengers. The weights of single passengers chosen at random have a mean of 65 kilograms and a standard deviation of 7 kilograms.
a. Calculate the mean of the total weights of the passengers.
b. Calculate the variance of the total weight of the 25 passengers
2. Nuts and bolts are used in the assembly of a part of the lift. The diameters of both nuts and bolts are normally distributed. The diameters of nuts vary randomly with a mean of 15.3 millimeters and standard deviation of 0.2 millimeters. The diameters of the bolts also vary randomly with a mean of 15.2 millimeters and a standard deviation of 0.1 millimeters.
a. Calculate the mean difference between the diameter of the nuts and the diameters of the bolts.
b. Calculate the variance of the difference between the diameter of the nuts and the diameter of the bolts.
Can you please give answers step by step and explain what you are doing.
Thanks so much!
1. A lift in a building carriers 25 passengers. The weights of single passengers chosen at random have a mean of 65 kilograms and a standard deviation of 7 kilograms.
a. Calculate the mean of the total weights of the passengers.
b. Calculate the variance of the total weight of the 25 passengers
2. Nuts and bolts are used in the assembly of a part of the lift. The diameters of both nuts and bolts are normally distributed. The diameters of nuts vary randomly with a mean of 15.3 millimeters and standard deviation of 0.2 millimeters. The diameters of the bolts also vary randomly with a mean of 15.2 millimeters and a standard deviation of 0.1 millimeters.
a. Calculate the mean difference between the diameter of the nuts and the diameters of the bolts.
b. Calculate the variance of the difference between the diameter of the nuts and the diameter of the bolts.
Can you please give answers step by step and explain what you are doing.
Thanks so much!
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