The standard deviation of 68 73 64 is: 4.5093
Chat with our AI personalities
The standard deviation of the scores 100 92 94 95 81 82 87 89 71 71 73 61 62 68 51 55 is: 15.1921
n probability theory and statistics, thestandard deviation of a statistical population, a data set, or a probability distribution is the square root of itsvariance. Standard deviation is a widely used measure of the variability ordispersion, being algebraically more tractable though practically less robustthan the expected deviation or average absolute deviation.It shows how much variation there is from the "average" (mean). A low standard deviation indicates that the data points tend to be very close to the mean, whereas high standard deviation indicates that the data are spread out over a large range of values.For example, the average height for adult men in the United States is about 70 inches (178 cm), with a standard deviation of around 3 in (8 cm). This means that most men (about 68 percent, assuming a normal distribution) have a height within 3 in (8 cm) of the mean (67-73 in (170-185 cm)) - one standard deviation, whereas almost all men (about 95%) have a height within 6 in (15 cm) of the mean (64-76 in (163-193 cm)) - 2 standard deviations. If the standard deviation were zero, then all men would be exactly 70 in (178 cm) high. If the standard deviation were 20 in (51 cm), then men would have much more variable heights, with a typical range of about 50 to 90 in (127 to 229 cm). Three standard deviations account for 99.7% of the sample population being studied, assuming the distribution is normal (bell-shaped).
64 64 64 65 65 65 65 67 67 68 68 70 70 72 73 76 79 80. NB Place the numbers in RANK order. In this case it is already done #1 MODE ; is the term that occurs most frequently. In this case it is '65' , as there are four lots of '65' #2 MEDIAN ; is the term that occurs at the ABSOLUTE middle of the ranked order. Since there are eighteen terms, there is no absolute middle term. So we take the two middle terms that have the same number of terms to their side, that is terms nine & ten. They are 67 & 68. We then add these two together and halve the result. Hence (67 + 68) / 2 = 67.5. This is the median term. #3 MEAN ; is the sum of all the terms, which is the divided by the number of terms. Hence (64+64+64+65+65+65+65+67+67+68+68+70+70+72+73+76+79+80)/18 = 69' NB Another way of calculating the mean is ((3x64)+(4x65)+(2x67)+(2x68)+(2x70)+72+73+76+79+80)/18 = 69 NNB The word 'average' is casually used in the non-mathematical world, but the correct term is MEAN.
73%
73