Statistics for MBA/ Business statistics explained by example

Examine central tendency, including mean, median, and mode, with arithmetic concepts, plus Excel calculations; and explore dispersion, such as range, variance, standard deviation, coefficient of variation, and z scores.

Learn how to compute the arithmetic mean, the most used measure of central tendency, using ungrouped and grouped data, with step-by-step Excel examples and the average function.

Highlight the advantages and disadvantages of the arithmetic mean as a central measure. It captures information from all observations yet is sensitive to extreme values and open-ended classes.

Calculate the weighted mean by multiplying each labour type's hours by its rate and summing the costs. Divide by the total hours to obtain the average cost per hour.

The range equals maximum minus minimum, offering an easy measure of spread, but it ignores variance among data points and is highly sensitive to outliers, making it an imperfect representation.

The lecture explains that the sum of squared distances from observations is minimized at the mean, and a constant prediction based on the mean minimizes squared error across all observations.

Compute the coefficient of variation by dividing the standard deviation by the mean to compare variability across units, and use z statistics to standardize observations.

Explore two practical exercises to calculate central tendencies and dispersion using Excel, including mean, median, and arithmetic mean from data and ranges, with an answer sheet for verification.

Explore normal distribution and the central limit theorem, their detailed properties, and how data take their shape, using Excel simulations to verify concepts.

Understand the normal distribution as a bell-shaped, symmetric curve where mean, median, and mode coincide. Standardize to z-scores to reveal 68.27% within one sd, 95.45% within two, 99.73% within three.

Normal distribution appears in nature as a bell-shaped curve, symmetric around the mean with most data near the center and fewer at the extremes.

Explore sampling statistics through examples of sample mean, median, variance, and standard deviation, and learn how these estimates relate to population parameters and percentiles.

the lecture shows the average of sample means equals the population mean and the standard deviation of sample means is sigma divided by sqrt(n), illustrating the central limit theorem.

Explore how sampling distributions of proportions behave like a normal curve as you take larger samples, using coin toss examples, and learn the standard deviation formula sqrt(p(1-p)/n) for proportion estimates.

Explains the sampling distributions of means and proportions for iid data, showing that the mean of sample means equals the population mean while standard deviations follow sd/sqrt(n) and sqrt(p(1-p)/n).

See how sample proportions follow a normal distribution and lead to a confidence interval. Using two standard deviations around the sample proportion, estimate the population proportion with 95 percent.

Compute a 95% confidence interval for the sample proportion, p-hat = 0.55, from 200 students, as an estimate of the population parameter, using the standard error and 1.96 multiplier.

The lecture explains constructing a confidence interval for the mean using the standard error sigma-hat over sqrt(n), rooted in the central limit theorem, with an Excel-based demonstration.

Demonstrates the t-distribution with an Excel-based simulation, compares it to the normal distribution, and teaches degrees of freedom and reading the t-table for confidence intervals.

Calculate a confidence interval for a small sample using a t-table with 9 degrees of freedom; for mean 11400 and sd 700, n=10, the 95% interval is 10899 to 11901.

Explore the criteria of a good estimator—unbiased, efficient, and consistent—using the sample mean to estimate population parameters and the impact of sample size on standard deviation.

Explore a business hypothesis testing example using copper wire diameter data to illustrate mean, standard deviation, normal distribution, and probability distributions, with Excel demonstrations.

Explain how to use a sample mean and a 99 percent threshold to verify a 4 mm wire claim, and determine when to reject an entire container.

Define Type I and II errors and the power of a test, then illustrate with a supplier risk example and central limit theorem using sample means.

Learn how to compute p-values for one-tailed and two-tailed tests from a cricket ball example, including Excel calculations and using the null hypothesis for hypothesis testing.

Demonstrates large sample and small sample hypothesis tests for mean and proportion using football diameter and coin bias examples, with an Excel workbook and step-by-step guidance.

Learn to select the correct statistic for hypothesis tests using a practical table, including z-tests, t-tests, one-sample proportion tests, and a medicine example.

Explore simple linear regression with an intuitive example, derive the ordinary least squares equation, and use Excel to estimate slope, correlation coefficient, and coefficient of determination.

Apply the ordinary least squares method to estimate y = a + b x by minimizing squared errors; a = ȳ − b x̄ and b = Σ(X−x̄)(Y−ȳ)/Σ(X−x̄)².

Learn Pearson's r, the correlation coefficient that quantifies the strength and direction of a linear relationship, with values from -1 to 1 and stronger relationships near the extremes.

Explore degree of freedom in contingency tables and its role in chi-square significance. Learn the formula df = (R-1)(C-1) and how to compare chi-square to critical values.

Learn how to perform a chi-square test in Excel, compare p-values across degrees of freedom, compute observed and expected counts, and identify which variable more strongly predicts the outcome.

Explore scenarios for one-way ANOVA across distinct groups, comparing means of scores, mileage, and bacteria counts to determine if group differences are due to treatment rather than chance.

Compute between sample variance by weighting each group's mean deviation from the grand mean with its sample size, then divide by the number of groups minus one, as shown in Excel.

Learn to calculate within-sample variance across multiple groups, weighting each variance by n_i−1, and obtain the pooled estimate of population variance with degrees of freedom N−k.

Analyze how samples from different populations affect variance: within-sample variance stays similar while between-sample variance grows when one sample is very different, yielding large f-statistics and supporting the alternate hypothesis.

Learn to run one-way ANOVA in Excel using the data analysis toolpak. The method computes between and within variances, F-statistics, and p-values, with clear interpretation at the 5 percent level.

Explore when to use non-parametric tests with ordinal data, ranks, and distribution-free assumptions, including real-life surveys and rank comparisons in physics and maths.

Understand the difference between monotony and linearity, and how monotonic versus linear relationships affect regression and non-parametric methods, with examples like y = a + b x.

Non-parametric methods offer distribution-free analysis for ordinal and nominal data with simple calculations and robustness, but they trade off lower power and larger sample needs.

Learn the Mann Whitney U test, a non-parametric rank-sum method to compare two independent samples and test if they come from the same population, using rank sums and U statistic.

Learn the Kruskal-Wallis H test for three independent samples, without distribution assumptions, using rank sums and a chi-square comparison, shown with video tutorials, study groups, and classroom training.