Please help me with these three problems. I will appreciate it if you could show me the working because I can't seem to wrap my head around them. 1. An online survey was conducted to study cyberbullying in the UK. It was reported that 62% of young people had received nasty private messages on a social network. You randomly sample four young people from the network and ask them if they received nasty messages on the network. Find the probability that the number who received these messages is three. A. .85 B. .74 C. .18 D. .36 2. The number of particles large enough to initiate a crack on an aircraft wing follows a Poisson distribution with mean 0.5 per square centimeter. Find the probability that a 100 square centimeter section has more than 60 of these particles. A. .207 B. .928 C. .027 D. .072 3. The following data represent the age (in weeks) at which babies first crawl based on a survey of 12 mothers. The age at which babies first crawl is known to be approximately normal. Construct a 99% confidence interval for the mean age at which babies first crawl. 52 30 44 35 39 26 47 37 65 26 39 28 A. 29.3 to 47.2 B. 28.6 to 49.4 C. 27.6 to 49.7 D. 28.9 to 47.6
Please help me with these three problems. I will appreciate it if you could show me the working because I can't seem to wrap my head around them.
1. An online survey was conducted to study cyberbullying in the UK. It was reported that 62% of young
people had received nasty private messages on a social network. You randomly sample four young people
from the network and ask them if they received nasty messages on the network. Find the
the number who received these messages is three.
A. .85
B. .74
C. .18
D. .36
2. The number of particles large enough to initiate a crack on an aircraft wing follows a Poisson distribution
with mean 0.5 per square centimeter. Find the probability that a 100 square centimeter section has more
than 60 of these particles.
A. .207
B. .928
C. .027
D. .072
3. The following data represent the age (in weeks) at which babies first crawl based on a survey of 12
mothers. The age at which babies first crawl is known to be approximately normal. Construct a 99%
confidence interval for the mean age at which babies first crawl.
52 30 44 35 39 26 47 37 65 26 39 28
A. 29.3 to 47.2
B. 28.6 to 49.4
C. 27.6 to 49.7
D. 28.9 to 47.6
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