HBX Business Analytics Questions and Answers (100% Correct Answers) Already Graded A+

Skewness [ Ans: ] Skewness measures the degree of a graph's asymmetry. If the right tail is longer, we say the distribution is skewed to the right or "right-tailed." Likewise, if the left tail is longer, we say the distribution is skewed to the left or "left-tailed." Rules of thumb for the normal distribution [ Ans: ] About 68% of the probability is contained in the range reaching one standard deviation away from the mean on either side: P(μ−σ≤x≤μ+σ)≈68% About 95% of the probability is contained in the range reaching two standard deviations (1.96 to be exact) away from the mean on either side: P(μ−2σ≤x≤μ+2σ)≈95% We'll use two standard deviations when discussing the normal distribution conceptually, but we will always use 1.96 for actual calculations in Excel. About 99.7% of the probability is contained in the range reaching three standard deviations away from the mean on either side: P(μ−3σ≤x≤μ+3σ)≈99.7% Bias [ Ans: ] avoid biased results by - phrasing questions neutrally -ensuring that the sampling method is appropriate for the demographic of the target population -pursuing a high response rate Normal Distribution [ Ans: ] a unique symmetrical shape whose centre and width are determined by its mean and standard deviation respectively. z-value [ Ans: ] the distance that x lies from the mean, measured in standard deviations. Central Limit Theorem [ Ans: ] If we take enough sufficiently large samples from any population, the means of those samples will be normally distributed regardless of the shape of the underlying population. Confidence interval [ Ans: ] An estimate of the range in which the true population mean likely lies. Outlier [ Ans: ] Technically, a data point is considered an outlier if it is more than a specified distance below the lower quartile or above the upper quartile of a data set. Let's start with a couple of definitions. The lower quartile, Q1, is the 25th percentile—by definition, 25% of all observations fall below Q1. The upper quartile, Q3, is the 75th percentile—75% of all observations fall below Q3. The interquartile range (IQR) is the difference between the upper and lower quartiles, that is, IQR=Q3-Q1. Histogram [ Ans: ] Histogram, also called a bar chart. A histogram's x-axis represents bins corresponding to ranges of data; its y-axis indicates the frequency of observations falling into each bin. Descriptive Statistic [ Ans: ] Provide a quick overview of a data set without showing every data point. Central Tendency [ Ans: ] "central tendency" of a data set—an indication of where the "center" of the data set lies. Mean [ Ans: ] Mean (average): The mean is equal to the sum of all of the data points in a set, divided by n, the number of data points.