Standard deviation - practice problems - page 5 of 6
Number of problems found: 118
- Bivariate data set
Here is a bivariate data set in which you believe y to be the response variable. x y 51.4 44.8 60.2 46.6 60.1 46.8 45.8 46.3 37.4 41.8 72.4 52.5 60 48.2 67.5 49.5 60.9 49.8 51.1 45.7 62.7 49.6 194.9 84.2 Make a scatter plot of this data. Which point is an
- Dataset:
Dataset: 35 22 18 54 22 46 28 31 43 22 14 17 25 19 33 14. 1 Group the data into a grouped distribution using six classes of equal width. 2. Determine the mean, median, and mode using the raw data. 3. Draw an Ogive curve corresponding to the data and use i
- Statistical survey
Write TRUE OR FALSE for each question: 1 Standard deviation measures central location. 2. The most frequent observation in a data set is known as the mode. 3 The most passive method of data collection is observation. 4 Access time for secondary data is sh
- A mountain climber
A mountain climber plans to buy some rope to use as a lifeline. Which of the following would be the better choice? Explain your choice. Rope A: Mean breaking strength:500lb; the standard deviation of 100lb Rope B: Mean breaking strength: 500lb; the standa
- Tallest people a
As a group, the Dutch are amongst the tallest people in the world. The average Dutchman is 184 cm tall. If a normal distribution is appropriate, and the standard deviation for Dutchmen is about 8 cm, what is the percentage of Dutchmen who will be over 2 m
- The raw
The raw data presented here are the scores (out of 100 marks) of a market survey regarding the acceptability of a new product launched by a company for a random sample of 50 respondents: 40 45 41 45 45 30 30 8 48 25 26 9 23 24 26 29 8 40 41 42 39 35 18 25
- Corresponding 33321
The following data on the height and the corresponding number of pupils were found in the measurement of 63 pupils: the height; number of pupils 159cm; 1 161cm; 1 162cm; 2 163cm; 1 164cm; 2 165cm; 2 166cm; 3 167cm; 2 168cm; 4 169cm; 3 170cm; 5 171cm; 6 17
- Statistical XY file
Year; money spent on advertising; profit (three values each row) 2008 2 12 2009 5 20 2010 7 25 2011 11 26 2012 15 40 1. draw a scatter diagram depicting the data. 2. calculate the Pearson's correlation coefficient. 3. determine the linear regression equat
- Marketing
Year; money spent on advertising; profit 2008 2 12 2009 5 20 2010 7 25 2011 11 26 2012 15 40 1. draw a scatter diagram depicting the data. 2. calculate the Pearson's correlation coefficient. 3. determine the linear regression equation.
- Complaints
The table is given: days; complaints 0-4; 2 5-9; 4 10-14; 8 15-19; 6 20-24; 4 25-29; 3 30-34; 3 1.1 What percentage of complaints were resolved within two weeks? 1.2 calculate the mean number of days to resolve these complaints. 1.3 calculate the modal nu
- Tennis aces
The number of aces served by Novak Djokovic in the last 20 tournaments he has participated in is shown below. 12 17 13 7 8 14 11 14 10 12 15 9 11 13 6 15 18 5 19 24 1.1 using the raw, determine the range. 1.2 Group the data into a frequency distribution w
- IQ Intelligence quotient
Intelligence quotient (IQ) is a standardized score used as the output of standardized intelligence psychological tests to quantify a person's intelligence with the rest of the population (respectively, to a given group). Intelligence has an approximately
- Assembly time
The assembly time for the toy follows a normal distribution with a mean of 75 minutes and a standard deviation of 9 minutes. The company closes at 5 pm every day. If one starts assembling at 4 pm, what is the probability that he will finish before the com
- Alopecia
Medical literature indicates that 45% of men suffer from alopecia. For a random sample of 8 men, calculate the probability that: (a) exactly four men suffer from alopecia. (b) at most, two men suffer from alopecia.
- Stoaches
Stoaches are fictional creatures distantly related to bigfoot and yeti. Stoach weights are normally distributed, with a mean of 904g and a standard deviation of 104g. State the probability that the sample mean of a random sample of 36 stoach weights excee
- Variability 29933
In September, students missed the following number of lessons: Girls: 2; 0; 7; 8; 2; 2; 4; Boys: 4; 4; 0; 3; 10; 3; 8; Compare the variability of both statistical files.
- Distribution 29371
Let the random variable ξ represent the number of satisfied customers. The probability of a satisfied customer for each of the four customers is 7/10. Specify: a) probability distribution, distribution function F(x) and P(-0.5 < ξ < 3.1) b) variance
- Lifespan
The lifetime of a light bulb is a random variable with a normal distribution of x = 300 hours, σ = 35 hours. a) What is the probability that a randomly selected light bulb will have a lifespan of more than 320 hours? b) To what value of L hours can the la
- Average height
There are twice as many girls in the class as there are boys. The average height of girls is 177 cm, and boys 186 cm. What is the average height of students in this class?
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