6-1 SmartBook Assignment: Chapter 7 (Sections 7.1 through 7.4)

Choose the correct Excel function to find P(X > 110) for a normal random variable with μ = 100 and σ = 20. Multiple choice question. NORM.DIST(110,100,20,1) 1-NORM.S.DIST(110,100,20,1) 1-NORM.DIST(20,110,100,1) 1-NORM.DIST(110,100,20,1)

1-NORM.DIST(110,100,20,1)

A random variable is said to be continuous if it Multiple select question. can have decimal values. has a countable number of values. is measured over an interval. has a countably infinite number of values.

1. Can have decimal values 2. Is measured over an interval

The normal distribution is the most extensively used distribution in statistical studies because Multiple select question. it is the simplest of all the probability distributions. many physical measurements have a bell-shaped distribution. economic and financial data often display bell-shaped distributions. it has important features used in sampling and estimation.

1. Many physical measurements have a bell-shaped distribution. 2. Economic and financial data often display bell-shaped distributions. 3. It has important features used in sampling and estimation.

A random variable with the continuous uniform distribution has which of the following characteristics? Multiple choice question. The probability distribution is bell shaped. The probability distribution is based on n independent trials. An equally likely chance of assuming any value within a specified range. Assumes the values 0, 1, 2, -- - - n with different probabilities.

An equally likely chance of assuming any value within a specified range.

Which of the following statements from the empirical rule is correct? Multiple choice question. Approximately 68% of values fall within 2 standard deviations of the mean for data with bell-shaped histograms. Approximately 65% of values fall within 2 standard deviations of the mean for data with bell-shaped histograms. Approximately 5% of values fall within 2 standard deviations of the mean for data with bell-shaped histograms. Approximately 95% of values fall within 2 standard deviations of the mean for data with a bell-shaped histogram.

Approximately 95% of values fall within 2 standard deviations of the mean for data with bell shaped histogram.

The probability that a discrete random variable equals any of its values is

Between zero and one, inclusive

Which of the following is an example of a discrete random variable? Multiple choice question. Exponential. Normal. Continuous uniform. Binomial.

Binomial

To find the P(Z ≤ -1.65) find the row containing __________ in the far left column. Then find the column containing ____________ in the top row. The intersection of this row and column is _______________(Round to 4 decimals).

Blank 1: -1.6 Blank 2: .05 Blank 3: .0495

To find P(0 ≤ Z ≤ 1.37) using Appendix C-1, find the row containing _________ in the far left column. Then find the column containing ________ in the top row. (Round the values to 2 decimal places.)

Blank 1: 1.30 Blank 2: 0.07

Any normal random variable X can be standardized by subtracting the __________ from x then dividing by the________ __________

Blank 1: mean or average Blank 2: standard Blank 3: deviation

A random variable with an equally likely chance of assuming any value within a specified range is said to have which distribution? Multiple choice question. Binomial distribution. Geometric distribution. Discrete uniform distribution. Continuous uniform distribution.

Continuous uniform distribution.

A random variable is said to be discrete if it has _____ Multiple choice question. infinitely uncountable number of values. countable number of values. if it can take on any value within an interval.

Countable number values

True or false: A continuous random variable can have a finite set of integer values.

False

For normally distributed random variables, how would one verify the empirical rule percentages using z scores? Multiple choice question. Find P(-1 ≤ Z ≤ 1) from a standard normal table and compare to 95%. Find P(-1 ≤ Z ≤ 1) from a standard normal table and compare to 68%. Find P(-2 ≤ Z ≤ 2) from a standard normal table and compare to 99.7%. Find P(-2 ≤ Z ≤ 2) from a standard normal table and compare to 68%.

Find P(-1 ≤ Z ≤ 1) from a standard normal table and compare to 68%.

The Normal distribution is also called the ______ distribution. Multiple choice question. Average Regular Gaussian Mission

Gaussian

Which of the following characteristics does NOT describe a Normal distribution? Multiple choice question. It has finite upper and lower limits. It is defined by μ and σ. The maximum height of the PDF is at μ. It is symmetric around its mean

It has finite upper and lower limits.

Which Excel expression would be used to find the X value associated with the highest 10% if X has a mean = 100 and a standard deviation = 20? Multiple choice question. NORM.S.INV(.90,100,20) NORM.INV(.10,100,20) NORM.INV(.90,100,20)

NORM.INV(.90,100,20)

Match the Excel normal CDF to the explanation NORM.S.DIST <----> ________ NORM.DIST <----> _______

NORM.S.DIST matches Area to the left of a z score. NORM.DIST matches Area to the left of a given x value

Choose the correct Excel function to find P(Z ≤0.87) Multiple choice question. NORM.DIST(.87,1) NORM.S.DIST(.87,1) 1-NORM.S.DIST(.87,1) NORM.S.DIST(.87,0)

NORM.S.DIST(.87,1)

Match the Excel normal CDF to the explanation NORM.S.INV <----> ________ NORM.INV<----> _______

NORM.S.INV matches Z score for a given cumulative area NORM.INV matches X value for a given cumulative area

Which of the following is an example of a continuous random variable? Multiple choice question. Normal. Poisson. Binomial. Discrete Uniform.

Normal

The standard deviation of the standard normal distribution is ______. Multiple choice question. one between zero and infinity greater than one less than one

One

Because the standard normal distribution is symmetrical about the mean 0, P(0 ≤ Z ≤ 1.96) is the same as Multiple choice question. P(0 ≤ X ≤ 1.96) P(0 ≤ Z ≤ -1.96) P(-1.96 ≤ Z ≤ 0) P(-1.96 ≤ Z ≤ 1.96)

P(-1.96 ≤ Z ≤ 0)

Which probability statement below represents a cumulative probability? Multiple choice question. P(0 ≤ Z ≤ 2.34) P(Z = -2.34) P(Z > -2.34) P(Z ≤ -2.34)

P(Z ≤ -2.34)

True or false: The uniform model is used only when you have no reason to imagine that any X-values are more likely than others.

True

True or false: Under appropriate circumstances, many discrete random variables can be described by the normal distribution.

True

An example of a random variable that closely follows the normal distribution is ______________. Multiple choice question. names of high schools in a city salary of NFL players scores on an easy statistics exam weight of a box of cookies

Weight of a box of cookies

An example of a random variable that closely follows the normal distribution is Multiple choice question. birth cities of newborn babies. names of males in USA. number of high schools in a city. weights of newborn babies.

Weights of newborn babies

Which of the following sample spaces would satisfy the definition of a continuous random variable? Multiple choice question. X = {odd integers between 5 and 15} X = {0,1,2,3} X = [0,500] X ={the number of days in the week that have the letter "r"}

X = [0,500]

The probability that a continuous random variable equals any of its values is

Zero

Consider a random variable X that denotes a random delivery time anywhere between 9 am and 10 am. X would reasonably be Multiple choice question. a negatively skewed random variable. a positively skewed random variable. a continuous uniform random variable. a discrete random variable.

a continuous uniform random variable.

The CDF for a continuous random variable gives the cumulative. (one word) under the PDF to the left of x.

area

The function used to find the area under the f(x) of a continuous random variable X up to any value x is called the binomial density function or BDF. the normal density function or NDF. the probability density function or PDF. the cumulative distribution function or CDF.

the cumulative distribution function or CDF