# Variance calculator

For variance calculation, please enter numerical data separated with comma (or space, tab, semicolon, or newline). For example: 520.6 296.4 891.6 482.6 402.3 114.3 428.1 511.7 -825.8 515.7 753.4 842.8 183.9### How to enter data as a frequency table?

Simple. Write data elements (separated by spaces or commas, etc.), then write f: and further write the frequency of each data item. Each element must have a defined frequency that counts numbers before and after symbol f: must be equal. For example:1.1 2.5 3.99

f: 5 10 15

### How to enter grouped data?

Grouped data are formed by aggregating individual data into groups so that a frequency distribution of these groups serves as a convenient means of summarizing or analyzing the data.group | frequency |

10-20 | 5 |

20-30 | 10 |

30-40 | 15 |

10-20 20-30 30-40

f: 5 10 15

### How to enter data as a cumulative frequency table?

Similar to a frequency table, but instead, f: write cf: in the second line. For example:10 20 30 40 50 60 70 80

cf: 5 13 20 32 60 80 90 100

The cumulative frequency is calculated by adding each frequency from a frequency distribution table to the sum of its predecessors. The last value will always equal the total for all observations since the calculator will have already added all frequencies to the previous total.

## Practice problems from statistics:

- 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. - A sample

A sample of 10 randomly selected students revealed the following grades in Business Statistics first test (in a marking scale of 0 to 100): 79, 63, 60, 45, 55, 58, 59, 62, 40, 68. Examine the data using groups and presenting: a) the Histogram of the absol - US GDP

Consider the following dataset, which contains the domestic US gross in millions of the top-grossing movies over the last five years. 300,452,513,550,780 I. Find the Mean of the Dataset II. Find the Squared deviation of the second observation from the mea - A sample 2

A sample of underweight babies was fed a special diet, and the following weight gains (lbs) were observed at the end of three months: 6.7, 2.7, 2.5, 3.6, 3.4, 4.1, 4.8, 5.9, and 8.3. Find the variance. (Round off to the nearest hundredths) - Distribution 2645

The worker operates 600 spindles on which the yarn is wound. The probability of tearing the yarn on each spindle at time t is 0.005. a) Determine the probability distribution of the number of torn spindles at time t and the mean and variance. b) What is t - Frequencies 81136

In grouped data classes such as 10-15, 16-20, 21-25, 26-30 with the respective frequencies of each class as 3, 5, 4, 3, then the range (range of variation) is: a. 15 b. 6 c. 20 d. 5 - The number 7

The number of faulty unit in a carton of a particular product is known to be normally distributed with Mean 10 and variance 25. What portion of a given carton of the product is expected to contain___ faulty units? (I) less than 8 (ii) more than 11 (iii) b - Balls

We have n identical balls (numbered 1-n) selected without replacement. Determine 1) The probability that at least one tensile strength number coincides with the number of balls? 2) Determine the mean and variance of the number of balls, which coincides wi - Variance and average

Of the 40 values were calculated average mx = 7.5 and variance sx = 2.25. After we found the control to lack the two items of the values of x41 = 3.8 and x42=7. Correct the above characteristics (mx and sx). - SD - mean

The mean is 10, and the standard deviation is 3.5. If the data set contains 40 data values, approximately how many of the data values will fall within the range of 6.5 to 13.5? - Three sigma rule

The height of trees in a given stand is known to be a quantity with a normal probability distribution with a mean value of 15 m and a variance of 5 m². Determine the interval in which there will be tree heights in such a stand with a probability of 90%

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