Please add other misleading numbers
but keep this as just a list of established points, with short definitions here and raise any disputes about them to new threads.

Mostly they suffer from imprecise or fuzzy definitions FD

1 home - unit of energy used by renewables
90% confidence level - as expressed in the IPCC's AR4
95% confidence - AR5
"97% of scientists say"

....
- I list other reasons why they are misleading below

1 home - implies that if we build windfarms to the level that the output in 'homes' equals the number of homes then the country will be producing no CO2 from electricity generation or even no CO2 at all but
// "Home" is a misleading unit - total power consumption in all forms is about 24x greater than "all homes" www.withouthotair.com/cI/page_329.shtml // tweeted David Mackay, the former chief scientist at DECC - 5 Jan 2015

90% confidence - FD it's an opinion pick from a confidence category rather than from a statistical analysis see Judy Curry
95% confidence - same
"97% of scientists say" - FD + no proper credible survey data exists : eg too small sample size etc

John Brignell of Numberwatch has an essay on stats abuse