Standard deviation - high school - practice problems
Number of problems found: 104
- 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? - 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? - Squared deviation
Given the data from the problem (sample data: 23, 27, 35, 44), find the sum of the squared deviations (the numerator of the fraction under the square root in the formula). In finding the number, round all calculations to 2 decimals (if you carry more or f - The mass 3
The mass of certain types of cabbage is normally distributed with a mean of 1000 g and a standard deviation of 0.15 kg. In a batch of 800 cabbages, estimate how many a mass between 750g and 1290g. - A sample variance
Calculate the value of the sample variance. −8,−8,−3,13,4,−8,10,8 - Compare variation
The mean blood pressure was 135 mmHg in a series of adults with a standard deviation of 10 mm Hg. In the same series, the mean height was 170 cm with a standard deviation of 6 cm. Find which character shows a greater variation (write A or B). - Q10 - investigate
A nutritionist who investigates fruits reported that the average weight of a raspberry is 4.4 g with a standard deviation of 1.28 g. What is the probability that a randomly selected raspberry would weigh less than 3.1 grams? Let X represent the weight of - 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 - Bulb life
Tests show that the lives of light bulbs are normally distributed with a mean of 750 hours and a standard deviation of 75 hours. Find the probability that a randomly selected light bulb will last between 675 and 900 hours. - Z-score calc
What is the Z Score for the following numbers: X is 16, and data for the population mean, and the standard deviation is 196, 193, 79, 30, 29, 81, 25, 21, 164 Level of difficulty = 2 of 2 Please format it to 2 decimal places. - 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? - 3 sigma
Students' performance scores in a statistic test have a mean of 70 and a standard deviation of 4.0. The scores obtained can be modeled by a normal distribution. Find the probability that the score of a randomly selected student is i. more than 80 marks ii - 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? - 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? - Suppose 8
Suppose the scores on a test have a normal distribution with X=74 and a standard deviation of s=18. What percentage of students have scores higher than 90? What percentage of students have scores between 70 and 85? Twenty percent of the students do better - Distributions 82068
Javelin throwers Anna and Barbora have average throw lengths of 67 m and 75 m, respectively, and standard deviations of 6 m and 3 m, respectively. Assume that the throw lengths have independent normal distributions. Calculate the probability that Anna thr - Distribution 82042
Assume that the IQ in the population follows a normal distribution with a mean of 100 points and a standard deviation of 10 points. With what probability among 15 randomly selected people: a. Is there anyone with an IQ above 130 points? b. Are there at le - Statistical 81497
Determine the median, mode, arithmetic mean, variance, standard deviation, range of variation, and coefficient of variation of the character x in the statistical file: 2x 9, 7x 10, 9x 11, 11x 15, 15x 17, 16x 19, 13x 21, 10x 25, 9x 29, 4x 32 - Confidence 80707
When checking the use-by date of a specific type of canned meat in warehouses of meat industry products, 340 canned goods were randomly selected, and it was found that 63 of them had passed their warranty period. Establish a 95% confidence interval to est - Characteristics: 80608
Arithmetic mean xA=40 and standard deviation sx=8 were calculated. Determine from which numbers the student calculated the given characteristics: a) 24 and 56 b) 16 and 64 c) 32 and 48
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