Bob and James are finishing the roof of a house. Working alone, Bob can shingle the roof in 14 hours. James can shingle the same
1 answer:
we know that Bob can do the whole job in 14 hours, how much of the work has he done in 1 hour only? well since he can do the whole lot in 14 hours in 1 hour he has only done 1/14 th of the job.
we know that James can do it in 18 hours, a bit slower, so in 1 hour he has done only 1/18 th of the job.
let's say it takes both of them working together say "t" hours, so in 1 hour Bob has done (1/14) of the work whilst James has done (1/18) of the work, the whole work being t/t or 1 whole, so for just one hour that'd 1/t done by both Bob and James.
You might be interested in
Answer:
1a) p-hat=0.38
1b) P=0.08
1c) The null hypothesis is not rejected
2a) p-hat=0.64
2b) P=0.0027
2c) The null hypothesis is rejected
3a) p-hat=0.55
3b) P=0.153
3c) The null hypothesis is not rejected
Step-by-step explanation:
(1) H0: p = 0.3 vs Ha: p ≠ 0.3. In their survey, they had a count of 38 using a sample size n=100.
1a) The p-hat is p-hat=38/100=0.38.
1b) The standard deviation is
The sample size is n=100.
The z-value is:
As it is a two-sided test, the p-value considers both tails of the distribution.
The p-value for this |z|=1.74 is P=0.08.
1c) The null hypothesis is not rejected.
(2) H0: p = 0.7 vs Ha: p ≠ 0.7. In their survey, they had a count of 320 using a sample size n=500.
2a) The p-hat is p-hat=320/500=0.64.
2b) The standard deviation is
The sample size is n=500.
The z-value is:
As it is a two-sided test, the p-value considers both tails of the distribution.
The p-value for this |z|=3 is P=0.0027.
2c) The null hypothesis is rejected.
(3) H0: p = 0.6 vs Ha: p < 0.6. In their survey, they had a count of 110 using a sample size n=200.
2a) The p-hat is p-hat=110/200=0.55.
2b) The standard deviation is
The sample size is n=200.
The z-value is:
As it is a two-sided test, the p-value considers both tails of the distribution.
The p-value for this |z|=1.43 is P=0.153.
2c) The null hypothesis is not rejected.