Question

**1)**

** A)** A market researcher analyzes
how many electronics devices customers buy in a single purchase.
The distribution has a mean of three with a standard deviation of
0.7. She samples 400 customers. What is the *z*-score for
Σ* x* = 1,186? (Enter an exact number as an integer,
fraction, or decimal.)

** B)** An unknown distribution has a
mean of 100, a standard deviation of 100, and a sample size of 100.
Let *X* = one object of interest.

What is * P*(Σ

** C)** The length of time a particular
smartphone's battery lasts follows an exponential distribution with
a mean of ten months. A sample of 64 of these smartphones is
taken.

Find the 85^{th} percentile for the total length of time 64
batteries last. (Round your answer to the nearest whole
number.)

Answer #1

1) An investment website can tell what devices are used to
access the site. The site managers wonder whether they should
enhance the facilities for trading via smartphones so they want to
estimate the proportion of users who access the site using
smartphones. They draw a random sample of 200 investors from their
customers. Suppose that the true proportion of smartphone users is
36%. a. What would you expect the shape of the sampling
distribution for the sample proportion to...

A. Quick Start Company makes 12-volt car batteries. After many
years of product testing, the company knows that the average life
of a Quick Start battery is normally distributed, with a mean of
44.2 months and a standard deviation of 7.7 months.
(a) If Quick Start guarantees a full refund on any battery that
fails within the 36-month period after purchase, what percentage of
its batteries will the company expect to replace? (Round your
answer to two decimal places.)
%...

1. Based on historical data, your manager believes that 34% of
the company's orders come from first-time customers. A random
sample of 91 orders will be used to estimate the proportion of
first-time-customers. What is the probability that the sample
proportion is greater than than 0.41?
2. A population of values has a normal distribution with
μ=163.2μ=163.2 and σ=78.9σ=78.9. You intend to draw a random sample
of size n=19.
What is the mean of the distribution of sample means?
μx¯=...

1. Using n – 1 in the denominator for the sample
variance is a much better estimate of the true population variance
when compared to dividing by n.
True
False
2.
During the 3 pm to 5 pm time period, cars arrive at a bank's
drive-through window at an average rate of 15 customers per hour.
Assume that the time between arrivals follows the exponential
distribution. What is the standard deviation for this probability
distribution?
a.
2 minutes
b.
4...

You are interested in finding out the mean number of customers
entering a 24-hour convenience store every 10-minutes. You suspect
this can be modeled by the Poisson distribution with a a mean of
λ=4.84 customers. You are to randomly pick n=74 10-minute time
frames, and observe the number of customers who enter the
convenience store in each. After which, you are to average the 74
counts you have. That is, compute the value of X (a) What can you
expect...

1. Customers at the local Subway store order an ice tea with
their meal 70% of the time. Use the Binomial distribution to find
the answer to the following.
Find the probability that among the next 8 customers, at least 3
will order ice tea with their meal: (to three places
after the decimal)
Of the next 8 customers, how many do you expect to order ice tea
with their meal? (to one place after the decimal)
2. The average score of...

Quick Start Company makes 12-volt car batteries. After many
years of product testing, the company knows that the average life
of a Quick Start battery is normally distributed, with a mean of
45.4 months and a standard deviation of 7.7 months.
(a) If Quick Start guarantees a full refund on any battery that
fails within the 36-month period after purchase, what percentage of
its batteries will the company expect to replace? (Round your
answer to two decimal places.)
%
(b)...

1. For a standard normal distribution, given:
P(z < c) = 0.9353
Find c.
2. A population of values has a normal distribution with
μ=195.6μ=195.6 and σ=42.9σ=42.9. You intend to draw a random sample
of size n=203n=203.
What is the mean of the distribution of sample means?
μ¯x=μx¯=
What is the standard deviation of the distribution of sample
means?
(Report answer accurate to 2 decimal places.)
σ¯x=σx¯=
3.A population of values has a normal distribution with
μ=5.8μ=5.8 and σ=80σ=80. You...

1 . A study of 5,000 American women was taken to determine the
mean number of children per household. Samples of 100 were taken by
state. The average American household, as reported by women,
contains 2.1 children with a standard deviation of 1.87. What would
be the mean of the sampling distribution of the sample means? (If
rounding is necessary, round to four decimal places).
2 . A study of 5,000 American women was taken to determine the
mean number...

Question 1 (1
point)
Suppose that a sample of size 60 is drawn from a population with
mean 88 and standard deviation 61 . Find the value of , the mean of
the distribution of sample means.
Wrtie only a number as your answer.
Your Answer:
Question 2 (1
point)
Suppose that a sample of size 68 is drawn from a population with
mean 64 and standard deviation 46 . Find the value of , the
standard deviation of the...

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