STT205
A survey asked people how often they exceed speed limits. The data are then categorized into the following contingency table of counts showing the relationship between age group and response.
Among people with age over 30, what's the "risk" of always exceeding the speed limit?
0.20
The sample mean (X ̅) of first n natural numbers is:
Which mean is most affected by extreme values?
Arithmetic mean
Which measure of dispersion is least affected by extreme values?
Quartile deviation
In a survey of companies, it was found that 45 were in the mining sector, 72 were in the financial sector, 32 were in the IT sector and 110 were in the production sector. If a company is selected at random, what is the probability that this company is not in the production sector?
0.575
The mean of hypergeometric distribution is
There are 6 pupils and 4 cats. In how many can they be seated in a row so that no cats sit together:
6! × 7P4
If the harmonic mean of the two numbers X1 and X2 is 6.4 if X2=16, then X1 is:
4
If all the items in a variable are non-zero and non-negative then:
Methods of organizing, summarizing, and presenting data in an informative way are called:
Descriptive statistics
______________ is used to determine something about a population on the basis of a sample
Inferential statistics
If quartile range is 24 then quartile deviation is
48
If arithmetic mean is multiplied by the coefficient of variation then the resulting value is classified as
standard deviation
If a value represents the 95th percentile, this means:
95% of all values are below this point
The difference between the first and third quartile is called the
interquartile range
The mode is best described as:
the most frequently occurring value
Summary and presentation of data in tabular form with several non-overlapping classes is
frequency distribution
In a given sports activity, the annual rate of accidents is of about 4 per thousand people. An insurance company has 3000 insured clients that practice such sports activity. A good approximation of the number of accident compensations the insurance company will have to pay in a given year is given by the distribution
Type of probability distribution whose standard deviation is one and mean is equal to zero is classified as
standard normal probability distribution
Formula to calculate standardized normal random variable is
In binomial distribution, formula of calculating standard deviation is
square root of npq
In standard normal probability distribution, z-score of distribution will be zero if
If z-score of normal distribution is 2.5, mean of distribution is 45 and standard deviation of normal distribution is 3 then value of x for a normal distribution is
37.5
If value of failure in binomial probability distribution is 0.70 and success is 0.30 and number of values in distribution are 7 then moment coefficient of kurtosis is
0.18
If occurrence of a statistical event A does not affect occurrence of event B and vice versa then these events are classified as
statistically independent events
Conditional probability of two independent events Y and Z can be written as
Measure of chance of an uncertain event in form of numerical figures is classified as
probability
Tail or head, one or zero and girl and boy are examples of
complementary events
When the coefficient of skewness is zero, the frequency curve is
Bell shaped
Which of the following sets of figures has the greatest variability (range)?
-2, 5, 8, 12
In a group of 6 boys and 44 girls, four children are to be selected. In how many different ways can they be selected such that at least one boy should be there?
209
In how many different ways can the letters of the word 'CORPORATION' be arranged so that the vowels always come together?
50400
In how many different ways can the letters of the word 'CORPORATION' be arranged so that the vowels always come together?
50400
Kurtosis defines peakness of curve in region which is
around the mode
For Karl Pearson's skewness coefficient value of skewness must be in limits
Statistical measures such as deciles, percentiles, median and quartiles are classified as part of
quartile system
A set of scores is presented in a histogram. The histogram shows a series of bars that tend to decrease in height from left to right. What is the shape of the distribution?
Positively skewed
Which of the following statements is not correct?
The bar in a column chart touches each other
Discrete variables and continuous variables are two types of
quantitative classification
Which of the following is a unit less measure of dispersion?
Coefficient of variation
If a constant 5 is added to each observation of a set, the mean is
Increased by 5
Which of the following statements is always correct?
Median = Q2 = D5 = P50
The mean of 10 observations is 10. All the observations are increased by 10%. The mean of increased observations will be:
11
In a survey of companies, it was found that 45 were in the mining sector, 72 were in the financial sector, 32 were in the IT sector and 110 were in the production sector. What is the likelihood that a randomly selected company is either a mining company or an IT company?
0.297
If A and B are mutually exclusive events with P(A) = 0.3 and P(B) = 0.5, then P (A u B) =
0.80
In random experiment, observations of random variable are classified as
trials
Consider probability distribution as standard normal, if value of μ is 75, value of x is 120 with unknown standard deviation of distribution then value of z-statistic
will be positive
If mean of binomial probability distribution is 25 then mean of Poisson probability distribution is
25
The arithmetic mean height of 50 students of a college is 5’8’’. The height of 30 of these is given in the frequency distribution below:
Approximately what is the arithmetic mean height of the remaining 20 students? _______
*5’9’’*
Age distribution of 200 employees of a firm is given below:
The mean wage rate is: _________ ____ (correct to 2 decimal places)
*59.00*
The frequency distribution of the hourly wage rate of 60 employees of a paper mill is as follows:
The mean wage rate is: _________ ____ (correct to 2 decimal places)
*59.00*
*18*
Data based on workers salary is given as: 2500, 2700, 2600, 2800, 2200, 2100, 2000, 2900, 3000, 2800, 2200, 2500, 2700, 2800, 2600; and number of classes desired is 10 then width of class interval is _______________
*100*
The number of clients that enter a given store each hour follows a Poisson distribution with mean 3.25. We assume independence between the diﬀerent hours. The probability that in a given hour exactly 5 clients enter the store is ________________
*0.1172*
In a given sports activity, the annual rate of accidents is of about 4 per thousand people. An insurance company has 3000 insured clients that practice such sports activity. A good approximation of the number of accident compensations the insurance company will have to pay in a given year is given by ______ distribution
*Poisson*
Mean of 10 items is 50 and S.D is 14. What is the sum of squares of all items? _________
*26960*
A box of nine golf gloves contains two left-handed and seven right handed gloves. If three gloves are selected without replacement, what is the probability that all of them are left handed? ___________
*Zero*
The mean and variance of 7 observations are 8 and 16. If 5 of the observations are 2, 4, 10, 12, 14 the remaining 2 observations are? __________
*6 and 8*
The number of partition values in case of quartiles is____________
*Three*
Which measure of dispersion ensures highest degree of reliability?_____
*Standard deviation*
The mode of a frequency distribution can be determined graphically by _______
*Histogram*
Mean deviation is Minimum when deviations are taken from_________
*Median*
Sampling is simply a process of learning about the __________________ on the basis of a sample drawn from it
*Population*
The mean deviation about median from the data: 340, 150, 210, 240, 300, 310, 320 ____________(correct to 1 decimal place)
*52.9*
A _____________________ variable is a variable whose values can theoretically take on an infinite number of values within a given range of values
*Continuous*
Out of all the 2-digit integers between 1 and 200, a 2- digit number has to be selected at random. What is the probability that the selected number is not divisible by 7?
*77/90*
A researcher is interested in the travel time of Utrecht University students to college. A group of 50 students is interviewed. Their mean travel time in 16.7 minutes. For this study the mean of 16.7 minutes is an example of a(n) ___
*Statistic*
The mean of 10 observations is 10. All the observations are increased by 10%. The mean of increased observations will be____
*11*
An arrangement of finite numbers of objects taken some or all at a time is called their_____
*Permutation*
If the harmonic mean of the two numbers X_1 and X_2 is 6.4 if X_2=16, then X_1 is ___
*4*
If quartile range is 24 then quartile deviation is_____
*48*
Suppose that a histogram of a data set is approximately symmetric and "bell shaped". Approximately percent of the observations are within one standard deviation of the mean
*68*
Suppose that a histogram of a data set is approximately symmetric and "bell shaped". Approximately percent of the observations are within two standard deviation of the mean
*95*
Histograms, pie charts and frequency polygons are all types of ____ dimension diagrams
*One*
Probability of success increases in binomial probability distribution if the value of probability of failure _________
*decreases*
If the value of x for normal distribution is 35, mean of normal distribution is 65 and standard deviation is 25 then standardized random variable is ___
*-1.2*
If mean of binomial probability distribution is 25 then mean of Poisson probability distribution is ______
*25*
If value of failure in binomial probability distribution is 0.70 and number of values in distribution are 7 then moment coefficient of kurtosis is ____
*0.18*
The set of all possible outcomes of a random experiment is known as ______
*Sample space*
A well-defined collection of objects is known as ____
*set*
If occurrence of one event prevents the occurrence of other event then the two events are classified as _________________ events
*Mutually exclusive*
If occurrence of one event affects or explains occurrence of other event then events are classified as ______________
*Dependent events*
If a bag contains three fruits, 16 percent are apples, 30 percent are oranges and 20 percent some other fruit that is neither oranges nor apples then probability of selecting an orange randomly is _________
*0.3*
Around central value of observations, extent to which values depart from normal distribution is classified as ______
*skewness*
Mean of binomial probability distribution is 857.6 and probability of success is 64%. The number of trials in this binomial distribution is ____
*81340*
Approach in probability in which all outcomes from an experiment are equally likely to occur or are mutually exclusive is called _________________ approach
*Classical*
If value of success in binomial probability distribution is 0.40 and failure is 0.60 and number of trials in this distribution are 5 then moment coefficient of skewness is _____
*0.167*
Out of 7 consonants and 4 vowels, how many words of 3 consonants and 2 vowels can be formed?_____
*25200*
The probability of success changes from trial to trial in ____________ distribution
*hypergeometric*
In a survey of companies, it was found that 45 were in the mining sector, 72 were in the financial sector, 32 were in the IT sector and 110 were in the production sector. What is the likelihood that a randomly selected company is either a mining company or an IT company?
*0.297*
Hypergeometric distribution has ___________ parameters
*Three*
Poisson distribution has ____________ parameters
*One*
In kurtosis, frequency curve which looks more peaked than normal curve of bell shaped distribution is classified as____
*leptokurtic*
2600 applications for home mortgage are received by a bank and probability of approval is 0.78 then standard deviation of binomial probability distribution is________
*446.16*
*Zero*
The average of the sum of squares of the deviations about mean is called____
*Variance*
A card is drawn from a well shuffled pack of playing cards. What is the probability that it is either a diamond or a king? _____
*4/13*
*0.8*