fix some minor typos

Author: obigriffith

_posts/0003-02-01-Expression.md

@@ -407,11 +407,10 @@ $RNA_HOME/ercc_spikein_analysis/
 
 Which expression estimation (read counts or TPM values) are better representing the known/expected ERCC concentrations?  Why?
 
-Some notes of interpretation
+Some notes on interpretation:
 
-- In general the expression estimates for ERCC transcripts we are getting from our data are highly correlated with the expected concentrations for the ERCC spike-in reagent
-- There are some ERRC transcripts that were not detected in our data at all (count and TPM of 0). These correspond to a range of expected concentrations in the spile-in reagent but they are all at the lower end. Essentially this indicates a sensitivity limitation. With our downsampled RNAseq data, we are failing to detect some of the less abundant spiked-in ERCC transcripts. This is probably hurting our R squared values slightly.
+- In general the expression estimates for ERCC transcripts we are getting from our data are highly correlated with the expected concentrations for the ERCC spike-in reagent.
+- There are some ERCC transcripts that were not detected in our data at all (count and TPM of 0). These correspond to a range of expected concentrations in the spike-in reagent but they are all at the lower end. Essentially this indicates a sensitivity limitation. With our downsampled RNAseq data, we are failing to detect some of the less abundant spiked-in ERCC transcripts. This is probably hurting our R squared values slightly.
 - We observed a wide range of observed expression values for ERCC transcripts in both mixes. Remember that both mixes have ERCCs at low, medium, high levels (spread over 5-6 orders of magnitude).  But between the two mixes the ERCCs at each expected concentration are different.
-- Details on the [ERCC spike-in reagent](https://rnabio.org/assets/module_1/ERCC.pdf)
-
+- More details on the [ERCC spike-in reagent](https://rnabio.org/assets/module_1/ERCC.pdf).