Statistics in bio.

• Higher temperature


  Molecules will move faster
• Greater concentration gradient


  Faster diffusion rate
• Thinner membrane


  Faster diffusion rate
• Mitochondria
• Plant cell
• Total Magnification = objective lens size x eyepiece lens size = 10 x 10 = 100x
• FOV = Diameter of microscope x 1000 = 3.5mm x 1000 = 3500µm
• Success criteria: calculate a mean for a given data set, distinguish between a null hypothesis and its alternative hypothesis, calculate a chi-squared value, interpret the significance of a chi-squared value by relating it to a confidence level (p-value), perform a t-test for data samples, and interpret the confidence level (p-value), apply a p-value to determine whether a null hypothesis can, or cannot, be rejected, interpret the statistical significance of data
• Descriptive statistics are used to describe patterns in data
• Measures of central tendency describe a set of data by identifying the central position. Mean, median, and mode are all measures of central tendency
• Mean


  Sum of all the values in the data set divided by the number of values in the data set
• The mean is susceptible to the influence of outliers. As the data becomes skewed, the mean gets dragged away from the typical value, losing its ability to provide the best central location for the data. In these instances, the median is a better measure of central tendency to use
• Median


  Middle score for a set of data that has been arranged in order of magnitude
• Mode


  Most frequent score in a data set
• Range


  Difference between the most extreme values in the set
• Determine the mean and range of the following data set: 1.11, 1.18, 1.02, 1.09, 1.10, 1.13, 1.12 = 1.107 Range: 1.18 – 1.02 = 0.16
• Determine the mean and range of the following data set: 25, 28, 22, 26 = 25.25 Range: 28 – 22 = 6
• Range = maximum value – minimum value
• Standard Deviation is a measure of the spread of scores within a set of data
• If a sample of results is held, but a statement about the population is desired, the sample standard deviation needs to be calculated
• The sample standard deviation formula is:
• The larger the standard deviation, the more spread out (flat) the distribution will be. A smaller standard deviation means the data values are not spread out, so the peak will be higher
• Excel can be used to determine mean, median, and mode
• Standard Error is a measure of the spread that expresses the statistical accuracy of an estimate
• Standard error is similar to standard deviation; however, while SD uses population data, SE uses sample data (statistics)
• The smaller the SE, the more representative the sample will be of the overall population. The higher the SE, the more spread out the data
• Confidence interval, in statistics, refers to the probability that a population parameter will fall between a set of values for a certain proportion of times
• Confidence intervals measure the degree of uncertainty or certainty in a sampling method
• The most commonly used value for confidence intervals is 95%, a range of values that you can be 95% certain contains the true mean of the population
• The narrower the range of interval values, the more confident (accurate) the data. Larger sample sizes have a decreased confidence interval range
• The narrower the range of interval values, the more confident (accurate) the data
• Larger sample sizes have a decreased confidence interval range
• Calculating confidence intervals


  Can be calculated on a graphics calculator
• Error bars are graphical representations of the variability of data and used on graphs to indicate the error or uncertainty in a reported measurement
• A "significant difference" means that the results are most likely not due to chance or sampling error
• Inferential statistics are used to draw conclusions based on collected data
• The null hypothesis assumes there is no statistical difference/relationship between the data sets
• The alternative hypothesis states there is a statistical difference/relationship between the data sets
• When a hypothesis test is performed, a p-value helps determine the significance of the results
• Hypothesis tests


  Used to test the validity (statistical significance) of a null hypothesis