Mrs. Dominguez asked her students to plot the number of books they read over the summer.
2 answers:
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Answer:
The answer is below
Step-by-step explanation:
Given that mean (μ) = 23 hours, standard deviation (σ) = 10 hours
a) The population is a group of self employed home based workers while the variable is the number of hours worked per week.
b) The mean of the distribution of sample means (also known as the Expected value of M) is equal to the population mean μ.
The standard deviation of the distribution of sample means is called the Standard Error of M, it is given by:
c)
d) The sample size has no effect on the mean, hence increasing the sample size does not change the mean.
The square root of sample size is inversely proportional to the standard deviation therefore increasing the sample size reduces the standard deviation.
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Answer:
obtuse
Step-by-step explanation:
The law of cosines tells you ...
b² = a² +c² -2ac·cos(B)
Substituting for a²+c² using the given equation, we have ...
b² = b²·cos(B)² -2ac·cos(B)
We can subtract b² to get a quadratic in standard form for cos(B).
b²·cos(B)² -2ac·cos(B) -b² = 0
Solving this using the quadratic formula gives ...
The fraction ac/b² is always positive, so the term on the right (the square root) is always greater than 1. The value of cos(B) cannot be greater than 1, so the only viable value for cos(B) is ...
The value of the radical is necessarily greater than ac/b², so cos(B) is necessarily negative. When cos(B) < 0, B > 90°. The triangle is obtuse.