According to the University of Nevada Center for Logistics Management, 6% of all mer-
chandise sold in the United States gets returned (BusinessWeek, January 1 5, 2007). A
Houston department store sampled 80 items sold in January and found that 12 of the items
were returned.
a. Construct a point estimate of the proportion of items returned for the population of
sales transactions at the Houston store.
b. Construct a 95% confidence interval for the porportion of returns at the Houston store.
c. Is the proportion of returns at the Houston store significantly different from the returns
for the nation as a whole? Provide statistical support for your answer.

a) The point estimate of the proportion of items returned for the population of

sales transactions at the Houston store = 12/80 = 0.15

b) The 95% confidence interval for the proportion of returns at the Houston store = [0.0718 < p < 0.2282].

c) Yes.

We set an hypothesis and construct a test statistics. The test statistics result gives us:

Z calculated  = 2.2545, and this gives us the p-value = 0.0121. We assumed 95% confident interval. Hence, the level of significance (α) = 5%. Conclusively, since the p-value ==> 0.0121 is less than (α) = 5%, the test is significant. Hence, the proportion of returns at the Houston store is significantly different from the returns  for the nation as a whole.

Step-by-step explanation:

a) Point estimate of the proportion = number of returned items/ total items sold = 12/80 = 0.15.

b) By formula of confident interval:

CI(95%) = p ± Z*,

CI(95%) = [0.0718 < p < 0.2282]

c) The hypothesis:

: The proportion of returns at the Houston store is not significantly different from the returns  for the nation as a whole.

: The proportion of returns at the Houston store is significantly different from the returns  for the nation as a whole.

The test statistics:

Z = , where is the proportion of nation returns.

Z calculated  = 2.2545, and this gives us the p-value = 0.0121. We assumed 95% confident interval. Hence, the level of significance (α) = 5%. Conclusively, since the p-value ==> 0.0121 is less than (α) = 5%, the test is significant. Hence, the proportion of returns at the Houston store is significantly different from the returns  for the nation as a whole.

what is the approximate angle of acb if abc is 25cm and the length of segment bc is 15

step-by-step explanation:

the answer is: d) o, f, and kr.

atomic radius of bromine (br) is 114 pm.

atomic radius of oxygen (o) is 73 pm.

atomic radius of fluorine (f) is 72 pm.

atomic radius of krypron (kr) is 112 pm.

the atomic radius of a chemical element is a measure of the size of its atom.

the atomic radius varies with increasing atomic number, but usually increases because of increasing of number of electrons.

the atomic radius decreases across the periods because an increasing number of protons, because greater attraction between the protons and electrons.