Standard deviation - practice problems - page 5 of 6
Number of problems found: 108
- Tennis aces
The number of aces served by Novak Djokovic in the last 20 tournaments that 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 distribut - 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, boys 186 cm. What is the average height of students in this class?
- Ball bearings
One bearing is selected from the shipment of ball bearings. It is known from previous deliveries that the inner bearing radius can be considered a normal N distribution (µ = 0.400, σ2 = 25.10^−6). Calculate the probability that the selected radius will ex - Life expectancy
The life expectancy of batteries has a normal distribution with a mean of 350 minutes and a standard deviation of 10 minutes. What is the range in minutes 68% of the batteries will last? What is the range in minutes? How long will approximately 99.7% of b - Statistician 7500
A statistician monitored the variance of monthly wages and found its value to be 640,000. Determine the standard deviation of salaries if there is a one-off increase: a) about CZK 1,800, b) about 5%. - Standard deviation
Find the standard deviation for the dataset (grouped data): Age (years); No. Of Persons 0-10 ; 15 10-20 ; 15 20-30 ; 23 30-40 ; 22 40-50 ; 25 50-60 ; 10 60-70 ; 5 70-80 ; 10 - Std-deviation
Calculate standard deviation for file: 63,65,68,69,69,72,75,76,77,79,79,80,82,83,84,88,90
- Grade point average
The average GPA is 2.78, with a standard deviation of 0.45. If GPA is normally distributed, what percentage of the students have the following GPAs? Solve for the z-score and report the appropriate percentage: a. Less than 2.30 b. Less than 2.00 c. More t - 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 - Distribution 6283
The life of the bulbs has a normal distribution with a mean value of 2000 hours and a standard deviation of 200 hours. What is the probability that the light bulb will last for at least 2100 hours? - Distribution 6282
The waiting time in the buffet is governed by the normal distribution with a mean value of 130 seconds and a variance of 400. What is the probability that someone will wait less than a minute and a half? - Variability
In the table bellow the number of wrong produced goods in two shifts: morning shift: 2; 0; 6; 10; 2; 2; 4; 2; 5; 2; afternoon shift: 4; 4; 0; 2; 10; 2; 6; 2; 3; 10; Compare the variability in both shifts, compare the average number of wrong goods on both
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