Mean + standard deviation - practice problems
Number of problems found: 97
- A sample variance
Calculate the value of the sample variance. −8,−8,−3,13,4,−8,10,8 - Z-score 3
A random variable X has a mean of 4 and a standard deviation of 2. What is the corresponding z-score for x = 7? - Dataset
Data: 11,15,11,16,12,17,13,21,14,21,15,22 Find dispersion of a given dataset. - 5-number summary
Given the following 5-number summary: 11, 19, 24, 30, 48, which of the statistics cannot be determined? - Five number summary
Find the five-number summary for these data and make a boxplot. 14,5,12,19,2,35,5,4,3,7,5,8 - Z score transformation
Suppose a distribution has a mean µ = 8 and standard deviation σ = 4. What is the value of x if it is z = +1.50? - IQ scores
IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. What percentage of the population scores higher than 125 on an IQ test? - Dataset 3
Given dataset: 31, 28, 31,30,31,30,31,31,30,31,30,31 1. Construct a frequency table. 2. Construct a histogram. 3. Compute the mean. 4. Compute the median. 5. Find the mode. 6. Compute the midrange. 7. Compute the standard deviation. - Distribution 6399
For the statistical file: 2.3; 3.4; 1.8; 3.2; 3.2; 1.9; 3.3; 4.5; 4.3; 5.0; 4.8; 4.3; 4.3; 1.9 Determine the sample variance and the median, and from the empirical distribution function, determine P (2.1 - The usage
The battery usage time installed in a particular smartphone has a Normal distribution with a mean of 25.2 hours and a standard deviation of 7.5 hours. What is the probability of usage time greater than 32? - Suppose 12
Suppose in a physics test involving 30 students, and four scored 75%, eight scored 60%, twelve scored 50%, and six scored 30%. Calculate the mean of the group and the standard deviation. - Probability 64174
The banker deals, on average, with five clients a day. Find the probability that the number of clients (in one day) will be greater than 4. - 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 67074
The time required to complete the test has a normal distribution with a mean of 50 minutes and a standard deviation of 10 minutes. What percentage of students take the test within 30 minutes? - The Uniform Distribution
The number of tickets purchased by an individual for Beckham colleges holiday music festival is uniformly distributed random variable ranging from 5 to 12. What is the standard deviation? - IQR and range
The times spent in minutes by 20 people waiting in a queue at the bank for a teller were: 3.4, 2.1, 3.8, 2.2, 4.5, 1.4, 0,0, 1.6, 4.8, 1.5, 1.9, 0, 3.6, 5.2, 2.7, 3.0, 0.8, 3.8, 5.2, Find the range and interquartile range of the waiting times. - Coefficient of skewness
For the data set whose Karl Pearson's Coefficient of skewness = -2.25, variance is 16, and Mean is 35, then its median value will be: - Lengths 6
Lengths of 130 tubes are measured. The arithmetic mean is 17.27 cm, and the standard deviation is 1.2 cm. How many tubes do have a length: a) between 16.5 cm and 18.1 cm b) greater than 17 cm - The profit 3
An investment's profit (or loss) is normally distributed with a mean of $11,200 and a standard deviation of $8,250. What is the probability of a loss rather than a profit? - Controller
Output Controller of the company in the control of 50 randomly selected products found that 37 of them had no defects, eight had only one flaw, three had two defects, and two products had three defects. Determine the standard deviation and coefficient of
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