STATS(lect-1)

Statistics for management Levin and rubintrimmed mean — in a data set having very high and very low values the extreme values are discarded from computing the mean(extremes are called as outlier)

mean is affected by extreme values whereas the median is not

median – generally when the values given have a huge deviation from each other median is used(we don’t ignore the outliers while taking median)

geometric mean – used to find the average rate of growth of a quantity over timeGEOMEAN formula in excel

growth factor(GF) = final val/initial valGF>1 increase in growth rate vice versa

Mode – a data set can have multiple modes but only one mean and median

Range – max value – min value

STATS(lect-2)

Standard deviation (SD)Average variation from the mean.It is an indication of how closely the data points are clustered about the mean.Greater the SD

Data set that has all values the same have 0 SD It is represented as the average distance of the data point form the mean of the data set(always examine the mean and the SD of a data set before coming to any conclusion) STDEV(formula in excel)

Variance = square of SD

Coefficient of variation (CV)- No unitCv=sd/mean

Higher dispersion indicates greater risk

Probability – a likelihood of an event to occur,laws of probability hold for large values

Sample point (SP) - basic outcome of an eventSample space – set

Types of probability

1 classical approach – getting the probability without performing the experiment

2 relative frequency approach – probability calculated using the prior results

3 subjective approach –

probability of an event(P) = no of outcomes where event occurs/total no of outcomes

mutually exclusive events

Joint Probability P(AB) = P(A) * P(B)