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  2. Standard penetration test - Wikipedia

    en.wikipedia.org/wiki/Standard_penetration_test

    The sum of the number of blows required for the second and third 15 cm (6 in) intervals of penetration is termed the "standard penetration resistance" or the "N-value". N-value provides an indication of the density of the ground, and it is used in many empirical geotechnical engineering formulae.

  3. Spt function - Wikipedia

    en.wikipedia.org/wiki/Spt_function

    The spt function (smallest parts function) is a function in number theory that counts the sum of the number of smallest parts in each integer partition of a positive integer. It is related to the partition function. [1] The first few values of spt(n) are: 1, 3, 5, 10, 14, 26, 35, 57, 80, 119, 161, 238, 315, 440, 589 ... (sequence A092269 in the ...

  4. Microsoft Excel - Wikipedia

    en.wikipedia.org/wiki/Microsoft_Excel

    Excel for the web is a free lightweight version of Microsoft Excel available as part of Office on the web, which also includes web versions of Microsoft Word and Microsoft PowerPoint. Excel for the web can display most of the features available in the desktop versions of Excel, although it may not be able to insert or edit them.

  5. Positive and negative predictive values - Wikipedia

    en.wikipedia.org/wiki/Positive_and_negative...

    The positive predictive value (PPV), or precision, is defined as = + = where a "true positive" is the event that the test makes a positive prediction, and the subject has a positive result under the gold standard, and a "false positive" is the event that the test makes a positive prediction, and the subject has a negative result under the gold standard.

  6. Standard score - Wikipedia

    en.wikipedia.org/wiki/Standard_score

    Comparison of the various grading methods in a normal distribution, including: standard deviations, cumulative percentages, percentile equivalents, z-scores, T-scores. In statistics, the standard score is the number of standard deviations by which the value of a raw score (i.e., an observed value or data point) is above or below the mean value of what is being observed or measured.

  7. Simple linear regression - Wikipedia

    en.wikipedia.org/wiki/Simple_linear_regression

    Under this assumption all formulas derived in the previous section remain valid, with the only exception that the quantile t* n−2 of Student's t distribution is replaced with the quantile q* of the standard normal distribution. Occasionally the fraction ⁠ 1 / n−2 ⁠ is replaced with ⁠ 1 / n ⁠.

  8. Present value - Wikipedia

    en.wikipedia.org/wiki/Present_value

    Equivalently C is the periodic loan repayment for a loan of PV extending over n periods at interest rate, i. The formula is valid (for positive n, i) for ni≤3. For completeness, for ni≥3 the approximation is . The formula can, under some circumstances, reduce the calculation to one of mental arithmetic alone.

  9. 68–95–99.7 rule - Wikipedia

    en.wikipedia.org/wiki/68–95–99.7_rule

    In statistics, the 68–95–99.7 rule, also known as the empirical rule, and sometimes abbreviated 3sr or 3 σ, is a shorthand used to remember the percentage of values that lie within an interval estimate in a normal distribution: approximately 68%, 95%, and 99.7% of the values lie within one, two, and three standard deviations of the mean ...