Arepeated-measures research study uses a total of 20 participants to compare two treatment conditions. if the results are used to construct a 95% confidence interval for the population mean difference, then the t values will bea) ±2.093b) ±2.861c) ±1.729d) ±2.539

Starting at home, emily traveled uphill to the hardware store for 606060 minutes at just 666 mph. she then traveled back home along the same path downhill at a speed of 121212 mph. what is her average speed for the entire trip from home to the hardware store and back?